Monday, May 19, 2025

Discussion on "Longest Nice Substring" Problem

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Just The Problem Text

Problem: Longest Nice Substring A string is considered "nice" if it contains equal numbers of vowels and consonants, and all characters are lowercase English letters. You are given a lowercase string s. Find the length of the longest contiguous "nice" substring. Input A single string s consisting of only lowercase English letters. 1 <= len(s) <= 1000 Output Print the length of the longest "nice" substring in s. Example Input abcdeiou Output 6 ~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~

Can you ask me a (that may be simple at rating of about 4/10) coding problem that tests problem solving skills of the candidate?

Absolutely! Here's a simple but insightful (4/10 difficulty) coding problem that tests:

  • Basic string manipulation

  • Loop logic

  • Attention to detail in pattern detection


๐Ÿ”น Problem: Longest Nice Substring

A string is considered "nice" if it contains equal numbers of vowels and consonants, and all characters are lowercase English letters.

You are given a lowercase string s. Find the length of the longest contiguous "nice" substring.


๐Ÿงช Input

A single string s consisting of only lowercase English letters.
1 <= len(s) <= 1000


๐Ÿ“ค Output

Print the length of the longest "nice" substring in s.


๐Ÿงพ Example

Input:

nginx
abcdeiou

Output:

6

Explanation:

The substring cdeiou has 3 consonants (c, d, e) and 3 vowels (i, o, u) → hence it's "nice".
Its length is 6.


๐ŸŽฏ What this tests:

  • Understanding of substrings

  • Frequency counting

  • Sliding window or brute-force optimization


Would you like a follow-up version that increases difficulty slightly (e.g., rating 6/10) by adding mixed-case handling or requiring lexicographically smallest nice substring?

can you share it's solution?

Certainly! Here's a straightforward solution using brute-force with optimizations, suitable for a 4/10 difficulty level.


Solution Explanation

  1. Iterate over all possible substrings of the given string s.

  2. For each substring:

    • Count the number of vowels and consonants.

    • If both are equal, it's a "nice" substring.

    • Track the maximum length found.

Since the max length of s is 1000, a brute-force approach with substring checks is still acceptable for small inputs.


๐Ÿง  Python Code

python
def is_vowel(ch): return ch in 'aeiou' def longest_nice_substring(s): n = len(s) max_len = 0 for i in range(n): vowels = 0 consonants = 0 for j in range(i, n): if is_vowel(s[j]): vowels += 1 else: consonants += 1 if vowels == consonants: max_len = max(max_len, j - i + 1) return max_len # Example usage s = input().strip() print(longest_nice_substring(s))

๐Ÿ“ˆ Time Complexity

  • Worst-case: O(n²) — due to checking all substrings.

  • But inner loop operations are O(1), making it acceptable for n ≤ 1000.


๐Ÿงช Test Example

Input:

nginx
abcdeiou

Output:

6

Nice substring: cdeiou


Would you like a more optimized version using prefix sums or a sliding window?

Yes, please share the optimized solution

Great! Here's an optimized solution using prefix sums and hash maps to reduce the time complexity from O(n²) to approximately O(n).


Optimized Approach: Prefix Sum + Hash Map

We treat:

  • vowel as +1

  • consonant as -1

We compute a running sum. If the same value has occurred before, then the substring in between has an equal number of vowels and consonants.


๐Ÿง  Python Code (Optimized):

python
def is_vowel(ch): return ch in 'aeiou' def longest_nice_substring(s): n = len(s) prefix_sum = 0 index_map = {0: -1} # sum -> earliest index max_len = 0 for i in range(n): if is_vowel(s[i]): prefix_sum += 1 else: prefix_sum -= 1 if prefix_sum in index_map: max_len = max(max_len, i - index_map[prefix_sum]) else: index_map[prefix_sum] = i return max_len # Example usage s = input().strip() print(longest_nice_substring(s))

๐Ÿ“ˆ Time and Space Complexity:

  • Time: O(n)

  • Space: O(n) (for the hashmap)


๐Ÿงช Example

Input:

nginx
aeiobcdfg

Output:

8

Explanation: eiobcdfg contains 4 vowels and 4 consonants.


Let me know if you'd like to extend this to handle uppercase, or allow more fine-tuned constraints like ignoring non-alphabetic characters.

Can you pls breakdown and explain this solution?

Absolutely! Let's break down the optimized solution step-by-step so you understand the logic and mechanics clearly.


๐Ÿ” Problem Recap

You are given a string of lowercase letters, and you must find the length of the longest substring that contains an equal number of vowels and consonants.


Key Insight:

We convert this into a running balance problem:

  • Every vowel is treated as +1

  • Every consonant is treated as -1

Now the goal becomes:
๐Ÿ‘‰ Find the longest substring where the total balance is zero, i.e., the number of vowels and consonants are equal.


๐Ÿงฑ Step-by-Step Explanation

Let's walk through this code:

1. Helper Function: To check for vowels

python
def is_vowel(ch): return ch in 'aeiou'

This simply checks if a character is a vowel.


2. Core Function Setup:

python
n = len(s) prefix_sum = 0 index_map = {0: -1} max_len = 0
  • prefix_sum: This keeps a running total:

    • +1 for vowels

    • -1 for consonants

  • index_map: Stores the first index at which each prefix sum value occurs.

    • Initially, we set 0: -1 to handle the case where the whole prefix from index 0 has a sum of 0.

  • max_len: Stores the length of the longest "nice" substring found.


3. Iterate Through the String:

python
for i in range(n): if is_vowel(s[i]): prefix_sum += 1 else: prefix_sum -= 1

As we go character by character, we update the prefix sum depending on whether we hit a vowel or consonant.


4. Check If Balance Seen Before:

python
if prefix_sum in index_map: max_len = max(max_len, i - index_map[prefix_sum]) else: index_map[prefix_sum] = i
  • If we’ve seen this prefix sum before, that means:

    • The substring between that earlier index and the current one has a net sum of 0, i.e., equal vowels and consonants.

    • So we calculate i - earlier_index and update the max_len accordingly.

  • If we haven’t seen this prefix sum before, we store the current index as the first occurrence.


๐Ÿ‘€ Example Walkthrough

Input:

ini
s = "aeiobcdfg"

Let's evaluate:

is[i]Is Vowel?prefix_sumSeen Before?Length if matchmax_len
0aYes+1No-0
1eYes+2No-0
2iYes+3No-0
3oYes+4No-0
4bNo+3Yes (@i=2)4 - 2 = 22
5cNo+2Yes (@i=1)5 - 1 = 44
6dNo+1Yes (@i=0)6 - 0 = 66
7fNo0Yes (@i=-1)7 - (-1) = 88
8gNo-1No-8

✅ Final answer: 8 (from index 0 to 7)


๐Ÿ“Š Final Notes

  • Time complexity: O(n) — you go through the string once.

  • Space complexity: O(n) — for storing prefix sum indices in the hashmap.


Let me know if you'd like a visual diagram or if you want to handle upper-case letters, other alphabets, or build a full working test harness.

Discussion on "Remove Consecutive Duplicates" Problem

To See All Articles About Technology: Index of Lessons in Technology
Problem: Remove Consecutive Duplicates

Given a string s, remove all consecutive duplicate characters and return the resulting string.

Input Format

A single line containing a string s (1 ≤ length of s ≤ 1000)

The string will contain only lowercase English letters.

Output Format

Print the string after removing consecutive duplicate characters.

Sample Input 1

aabbccddeee

Sample Output 1

abcde

Sample Input 2

aabaaabb

Sample Output 2

abab

~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~*~

Can you ask me a (that may be simple at rating of about 3/10) coding problem that tests problem solving skills of the candidate?

Sure! Here's a simple (3/10 difficulty) coding problem that tests basic problem-solving, string handling, and logic skills:


Problem: Remove Consecutive Duplicates

Given a string s, remove all consecutive duplicate characters and return the resulting string.


๐Ÿ”น Input Format

  • A single line containing a string s (1 ≤ length of s ≤ 1000)

  • The string will contain only lowercase English letters.


๐Ÿ”น Output Format

  • Print the string after removing consecutive duplicate characters.


๐Ÿ”น Sample Input 1

nginx
aabbccddeee

๐Ÿ”น Sample Output 1

nginx
abcde

๐Ÿ”น Sample Input 2

nginx
aabaaabb

๐Ÿ”น Sample Output 2

nginx
abab

๐Ÿง  What it tests

  • Understanding of string traversal

  • Use of conditionals

  • Handling edge cases like repeated or single characters


Let me know when you're ready for the solution or hints!

Can you critique this rough algo:

s = "afafasgggewrtdg"
t = ""
last_seen_character = ''
streak_found = False
for c in s: 
    if c not in t: 
        t += c
        last_seen_character = c
    elif c in t and last_seen_character == c: 
        streak_found = True
        last_seen_character = c
        continue
    else (c in t) and last_seen_character != c and not streak_found:
        t += c
        last_seen_character = c
        streak_found = False

Thanks for sharing your rough algorithm! You're clearly thinking through the logic and edge cases, which is great. Let’s break down the approach and evaluate it step by step.


๐Ÿ” Your Goal:

You want to remove consecutive duplicate characters from a string.


What’s good in your approach:

  1. Tracking state: You're maintaining last_seen_character — that’s useful for detecting consecutive repeats.

  2. Use of flags: You introduced streak_found to handle streaks, though it's a bit more complex than needed for this problem.

  3. Good intent: You’re trying to avoid adding characters that have already been added if they’re part of a consecutive streak.


Issues in the Logic:

  1. Wrong check for character presence in t:

    • You’re checking if c not in t, but this checks if the character has ever occurred in t, not if it's the same as the previous one.

    • This can cause issues with strings like "aabaaabb" — you'll incorrectly skip valid characters.

  2. Incorrect else condition:

    • Python syntax error: else (c in t) and ... is invalid.

    • else doesn’t take a condition. You’d need to use elif again.

  3. Unnecessary use of streak_found:

    • You don’t need a streak_found flag. You only need to compare each character to the one immediately before it.

  4. Adding characters that are not duplicates but previously seen:

    • You're preventing characters from being added again even if they're not consecutive — which is incorrect.


Correct Logic Should Be:

Keep the character only if it’s not equal to the previous character.


✔️ Cleaned Up Version of the Algorithm:

python
s = "afafasgggewrtdg" t = "" last_seen_character = None for c in s: if c != last_seen_character: t += c last_seen_character = c print(t)

๐Ÿงช Example:

Input: "aabaaabb"
Output: "abab"


⏱️ Time Complexity: O(n)

You visit each character once.

๐Ÿ“ฆ Space Complexity: O(n)

In the worst case, the output string could be the same length as input.


๐Ÿง  Final Thoughts:

You're on the right track with tracking characters, but overcomplicating it with multiple conditions and flags. Stick to comparing only the current and previous characters — that’s sufficient here.

Let me know if you want to walk through more test cases or edge conditions!


So The Solution Is:

s = "afafasgggewrtdg"
t = ""
last_seen_character = None

for c in s:
    if c != last_seen_character:
        t += c
    last_seen_character = c

print(t)

Sunday, May 18, 2025

AI Revolution Is Underhyped (Eric Schmidt at TED)

To See All Articles About Technology: Index of Lessons in Technology

AI’s Quantum Leap: Eric Schmidt on the Future of Intelligence, Global Tensions, and Humanity’s Role

The AlphaGo Moment: When AI Rewrote 2,500 Years of Strategy

In 2016, an AI named AlphaGo made history. In a game of Go—a 2,500-year-old strategy game revered for its complexity—it executed a move no human had ever conceived. "The system was designed to always maintain a >50% chance of winning," explains Eric Schmidt, former Google CEO. "It invented something new." This moment, he argues, marked the quiet dawn of the AI revolution. While the public fixated on ChatGPT’s rise a decade later, insiders saw the seeds of transformation in AlphaGo’s ingenuity.

For Schmidt, this wasn’t just about games. It signaled AI’s potential to rethink problems humans believed they’d mastered. "How could a machine devise strategies billions of humans never imagined?" he asks. The answer lies in reinforcement learning—a paradigm where AI learns through trial, error, and reward. Today, systems like OpenAI’s "3o" or DeepSeek’s "R1" use this to simulate planning cycles, iterating solutions faster than any team of engineers. Schmidt himself uses AI to navigate complex fields like rocketry, generating deep technical papers in minutes. "The compute power behind 15 minutes of these systems is extraordinary," he notes.


AI’s Underhyped Frontier: From Language to Strategy

While ChatGPT dazzles with verbal fluency, Schmidt insists AI’s true potential lies beyond language. "We’re shifting from language models to strategic agents," he says. Imagine AI "agents" automating entire business processes—finance, logistics, R&D—communicating in plain English. "They’ll concatenate tasks, learn while planning, and optimize outcomes in real time," he explains.

But this requires staggering computational power. Training these systems demands energy equivalent to "90 nuclear plants" in the U.S. alone—a hurdle Schmidt calls "a major national crisis." With global rivals like China and the UAE racing to build 10-gigawatt data centers, the energy bottleneck threatens to throttle progress. Meanwhile, AI’s hunger for data has outpaced the public internet. "We’ve run out of tokens," Schmidt admits. "Now we must generate synthetic data—and fast."


The US-China AI Race: A New Cold War?

Geopolitics looms large. Schmidt warns of a "defining battle" between the U.S. and China over AI supremacy. While the U.S. prioritizes closed, secure models, China leans into open-source frameworks like DeepSeek—efficient systems accessible to all. "China’s open-source approach could democratize AI… or weaponize it," Schmidt cautions.

The stakes? Mutual assured disruption. If one nation pulls ahead in developing superintelligent AI, rivals may resort to sabotage. "Imagine hacking data centers or even bombing them," Schmidt says grimly. Drawing parallels to nuclear deterrence, he highlights the lack of diplomatic frameworks to manage AI-driven conflicts. "We’re replaying 1914," he warns, referencing Kissinger’s fear of accidental war. "We need rules before it’s too late."


Ethical Dilemmas: Safety vs. Surveillance

AI’s dual-use nature—beneficial yet dangerous—forces hard choices. Preventing misuse (e.g., bioweapons, cyberattacks) risks creating a surveillance state. Schmidt advocates for cryptographic "proof of personhood" without sacrificing privacy: "Zero-knowledge proofs can verify humanity without exposing identities."

He also stresses maintaining "meaningful human control," citing the U.S. military’s doctrine. Yet he critiques heavy-handed regulation: "Stopping AI development in a competitive global market is naive. Instead, build guardrails."


AI’s Brightest Promises: Curing Disease, Unlocking Physics, and Educating Billions

Despite risks, Schmidt radiates optimism. AI could eradicate diseases by accelerating drug discovery: "One nonprofit aims to map all ‘druggable’ human targets in two years." Another startup claims to slash clinical trial costs tenfold.

In education, AI tutors could personalize learning for every child, in every language. In science, it might crack mysteries like dark matter or revolutionize material science. "Why don’t we have these tools yet?" Schmidt challenges. "The tech exists—we lack economic will."


Humans in an AI World: Lawyers, Politicians, and Productivity Paradoxes

If AI masters "economically productive tasks," what’s left for humans? "We won’t sip piรฑa coladas," Schmidt laughs. Instead, he envisions a productivity boom—30% annual growth—driven by AI augmenting workers. Lawyers will craft "smarter lawsuits," politicians wield "slicker propaganda," and societies support aging populations via AI-driven efficiency.

Yet he dismisses universal basic income as a panacea: "Humans crave purpose. AI won’t eliminate jobs—it’ll redefine them."


Schmidt’s Advice: Ride the Wave

To navigate this "insane moment," Schmidt offers two mandates:

  1. Adopt AI or Become Irrelevant: "If you’re not using AI, your competitors are."

  2. Think Marathon, Not Sprint: "Progress is exponential. What’s impossible today will be mundane tomorrow."

He cites Anthropic’s AI models interfacing directly with databases—no middleware needed—as proof of rapid disruption. "This isn’t sci-fi. It’s happening now."


Conclusion: The Most Important Century

Schmidt calls AI "the most significant shift in 500 years—maybe 1,000." Its promise—curing disease, democratizing education—is matched only by its perils: geopolitical strife, existential risk. "Don’t screw it up," he urges. For Schmidt, the path forward hinges on ethical vigilance, global cooperation, and relentless innovation. "Ride the wave daily. This isn’t a spectator sport—it’s our future."


Tags: Technology,Artificial Intelligence,Agentic AI,Generative AI,

6 Months to Financial Freedom - A Step-by-Step Guide for Every Income Level


Lessons in Investing

Introduction
Whether you earn ₹15,000 or ₹1.5 lakh a month, financial freedom isn’t a myth—it’s a mindset. Over the next six months, this plan will transform how you manage money, eliminate debt, and build wealth, one small step at a time. No jargon, no shortcuts—just actionable strategies to reclaim control of your finances. Let’s begin.


Month 1: Face Your Finances (Stop the Ostrich Effect)

The Problem: We often bury our heads in the sand, ignoring bills, loans, and reckless spending.
The Fix: Track every expense—UPI payments, EMIs, cash spends—in real time. Use apps like ET Money, Walnut, or a simple Excel sheet.

Action Steps:

  1. Log Daily: Note every ₹17 spent. No exceptions.

  2. Categorize:

    • Needs: Rent, groceries, utilities.

    • Wants: Dining out, gadgets, vacations.

    • Investments: Future-focused spending (even if it’s ₹0 now).

  3. Analyze: By month-end, you’ll uncover surprises (“I spent HOW MUCH on Zomato?!”).

Why It Works: Awareness is the first step to control.


Month 2: Build Your Safety Net

The Analogy: Imagine a circus safety net. Your finances need one too.
The Goal: Save 1 month’s essential expenses. If your needs cost ₹20,000/month, save ₹20,000.

How:

  1. Trim Surprises: Cancel unused subscriptions (₹2,500 gym membership you haven’t touched).

  2. Temporarily Cut Wants: Skip impulse purchases for 1–2 months.

  3. Save Relentlessly: No, you won’t starve—this is a short-term hustle.

Outcome: A ₹20K buffer means you’re protected if income stops suddenly.


Month 3: Crush Bad Debt

The Reality: Debt is a silent dream-killer.
The Strategy:

  1. List All Debts: Credit cards, personal loans, EMIs.

  2. Separate Good vs. Bad Debt:

    • Good Debt: Education loans, home loans (assets that grow in value).

    • Bad Debt: Credit cards (35% interest!), luxury car loans (depreciating liabilities).

  3. Snowball Method: Pay off the smallest debt first. Celebrate each win—it builds momentum.

My Story: I cleared ₹50 lakh in loans over 12 years. Slow and steady works.


Month 4: Start Investing (Even ₹500 Matters)

The Basics:

  1. Automate Savings: EPF, PPF, NPS (safe but low returns).

  2. Index Funds: Invest in Nifty 50 or Nifty Next 50 via SIPs. Let experts manage the risk.

  3. Insurance:

    • Term Life Insurance: ₹1 crore cover for minimal premium.

    • Health Insurance: Separate policies for parents to avoid premium spikes.

Rule of Thumb:

  • 25 years old? Allocate 25% of investments to safe assets (gold, debt funds).

  • 40 years old? 40% to safe assets. The rest? Let the stock market grow your wealth.


Month 5: Boost Your Income

Mindset Shift: Cutting expenses has limits—earning potential doesn’t.
Ways to Earn More:

  1. Upskill: Learn AI/ML, coding, or freelancing.

  2. Side Hustles: Tutoring, consulting, selling digital products.

  3. Negotiate: Ask for a raise or switch jobs.

Example: A ₹10,000/month side gig = ₹1.2 lakh/year extra. Invest 50%, enjoy 50%.


Month 6: Automate Everything

The Goal: Remove willpower from the equation.
Steps:

  1. Auto-Pay Bills: Set up standing instructions for EMIs, SIPs.

  2. Invest First: Automate SIPs on payday—no temptation to spend.

  3. Track Digitally: Use apps for real-time visibility into cash flow.

Outcome: Money works for you while you sleep.


Conclusion: The Rich Mindset

True wealth isn’t about crores in the bank—it’s about control. After six months, you’ll:

  • Track every rupee.

  • Have zero bad debt.

  • Invest consistently.

  • Earn with purpose.

Final Truth: The “rich” aren’t lucky. They’re disciplined. Start today, and time will do the rest.


P.S. This plan is inspired by my own journey from ₹50 lakh in debt to financial freedom. If I did it, so can you. ๐Ÿš€

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Saturday, May 17, 2025

Gate Drama, Late Thoughts, and the Elusive Idea of Success (2025-May-17 Evening)


Other Journaling Days

It started with a simple call.

Mahi was at the main gate, and the guard had asked her which flat she came from. She called me, a bit flustered. “What was your flat number, uncle, I forgot?” she asked. I said 'no problem', then told her to hand the phone to the guard at the exit.

I heard a voice mutter, “Yeh H2503 kiska hai?” And then, just like that, they let her through.

But something about it lingered.

Should I have told the guards earlier that Mahi is my niece—bhatiji? Would that have made things simpler? Why didn’t she just tell them herself that she had come to see her chacha? Why did this tiny situation trigger such unease in me?

And then my thoughts spiraled. I found myself questioning Moni’s decision to take Mahi to the temple. Was it even necessary? What if something had gone wrong at the gate? What if Moni returns and blames me—for not doing more, for not handling it better?

In my mind, I was already labeled: a loser, a coward. And Moni? Careless, laparwah.

But then, both Mahi and Moni returned. No drama. No tension. Just calm. The storm had only existed in my head.


I went to bed early that night, around 9:10 PM. Slept nearly 11.5 hours. Maybe my mind needed the rest. It was 11:07 AM when I finally sat down to reflect, prompted by a video: “Is Wealth the Problem? – Buddha’s Teaching on Success and Wealth.”

It stirred something deeper.

What am I chasing? What does success mean to me?

Honestly, I think I’m chasing peace. And the money? It's more about paying off debts than it is about greed. I don’t want riches—I want relief. I want space to breathe.

Do I want to be successful? Yes. But not with passion. Just as a vague checkbox. Because success, to me, has no clear definition. I don't know who is truly successful. I only see the superficial markers—cars, money, homes.

Do I equate money with success? Not really. Maybe 20% of me does. But I know, deep down, that money isn't everything.

Still, I’m left with the biggest question: What does success mean to me?

I don’t know yet. But I know this—it’s not happiness.

Namo Buddhaye.

A Lazy Afternoon, Some Interviews, and a Cup of Tea I Never Had (2025-May-17)


Other Journaling Days

It’s 3:25 PM. Slightly more than half a day has passed, and as I sit back to reflect, I’d say it’s been… good. Two interviews were scheduled. The first never happened—Priyanshi forgot to open the bridge. The second, set for 1 PM, was 40 minutes late. Same reason. Thankfully, Deepshika stepped in and salvaged the situation. All part of a regular day in corporate life, I guess.

“How am I feeling this afternoon?”
Lazy. The kind of lazy that comes from skipping my afternoon tea. It’s the weekend, so I decided to let my body recharge naturally. No caffeine, no boost—just silence, and a slowly settling fog of drowsiness.

I often feel like this. Tired. Sometimes confused when work drags into the afternoon. That’s usually when I crave tea—not for the taste, but for clarity.

But today was different.

I took a nap. I had a samosa. Simple joys. And then I meditated—just 20 minutes, but enough to shift my state of mind.

In that stillness, I revisited a powerful question:
“What would I do if this were my last day on Earth?”

Mahatma Gandhi’s words echoed in my head: “Live as if you were to die tomorrow. Learn as if you were to live forever.”

So, I read. That’s what I’d like to do—read. I’m currently deep into Ankur Warikoo’s self-help series. After finishing Do Epic Shit, I’m now on Get Epic Shit Done, with Make Epic Money and Build an Epic Career next in line. The titles may be bold, but the reflections within are grounding.

Then something mildly strange happened.

Just as I sat down to meditate, Megha pinged. She’s based in the UK and mentioned she'll be in India in August or September—which, to me, feels like a lifetime away. Our chat was short, slightly awkward. Maybe because I said I was meditating. Maybe because I replied with big smiling eyes and she replied with button-eyed emojis. Who knows?

Should I be offended? Probably not.
Should I be amused? Absolutely.

And that, dear reader, was my Saturday. No tea. Some quiet. A little soul-searching. And a reminder that even awkward texts are part of the human experience.

God bless.