🚀 DSA Daily – C++ Problem Solving Repository

Welcome to DSA Daily, a curated collection of my Data Structures & Algorithms (DSA) practice in C++ — aimed at mastering FAANG-level and Quant-level problem-solving.

This repository is a daily log of my journey to become fluent in algorithmic thinking, code optimization, and problem analysis.

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📊 Quick Profile Snapshot

Platform	Handle	Stats (as of Nov 2025)
🟩 LeetCode	anNTyyxxlo	🧩 67 problems solved • ⚔️ Contest Rating: 1727 (Top 11%)
🟠 Codeforces	Coming soon	Focus: algorithmic speed & optimization
🟢 GeeksforGeeks	Private logs	Focus: concept reinforcement & detailed notes

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🧠 Focus Areas

1️⃣ Core Data Structures

• Arrays, Strings, Linked Lists
• Stacks, Queues, Deques
• Trees (BST, Segment Trees, Tries)
• Heaps, Graphs, Hash Maps

2️⃣ Core Algorithms

• Sorting & Searching
• Sliding Window, Two Pointers
• Recursion & Backtracking
• Divide & Conquer
• Greedy, Bit Manipulation
• Dynamic Programming (1D, 2D, Space Optimized)
• Graph Algorithms: BFS, DFS, Dijkstra, Union-Find, Topological Sort

3️⃣ Advanced Topics

• Binary Search on Answers
• DP Optimization (State Compression, Tabulation)
• Prefix-Suffix Patterns
• Number Theory, Probability, and Combinatorics
• Quant-style Math & Logic Problems

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🏗️ Repository Structure

All .cpp files are stored directly in the main directory for quick access.

📁 DSA-Daily/ │ ├── array_two_sum.cpp ├── array_max_subarray_kadane.cpp ├── dp_longest_increasing_subsequence.cpp ├── dp_knapsack_01.cpp ├── graph_dijkstra.cpp ├── graph_bfs.cpp ├── string_longest_palindrome.cpp ├── linkedlist_reverse.cpp ├── problem_index.csv └── README.md

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📘 Problem Index Example

#	Problem	Category	Platform	Difficulty	Concept	File
1	Two Sum	Array	LeetCode	Easy	Hashmap	array_two_sum.cpp
2	Max Subarray (Kadane)	Array	GFG	Medium	Kadane’s Algorithm	array_max_subarray_kadane.cpp
3	Longest Increasing Subsequence	DP	LeetCode	Medium	DP + Binary Search	dp_longest_increasing_subsequence.cpp
4	Dijkstra’s Algorithm	Graph	LeetCode	Medium	Shortest Path	graph_dijkstra.cpp
5	Reverse Linked List	Linked List	LeetCode	Easy	Iterative / Recursive	linkedlist_reverse.cpp

Full list tracked in problem_index.csv

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⚙️ Example Code Snippet

🔹 Example: Longest Substring Without Repeating Characters

// Author: Gaurav Sah
// Problem: Longest Substring Without Repeating Characters
// Platform: LeetCode
// Approach: Sliding Window + Hashmap
// Time Complexity: O(n)
// Space Complexity: O(256)

#include <bits/stdc++.h>
using namespace std;

int lengthOfLongestSubstring(string s) {
    vector<int> last(256, -1);
    int maxLen = 0, start = 0;

    for (int end = 0; end < s.size(); ++end) {
        if (last[s[end]] >= start)
            start = last[s[end]] + 1;

        last[s[end]] = end;
        maxLen = max(maxLen, end - start + 1);
    }

    return maxLen;
}

int main() {
    string s = "abcabcbb";
    cout << lengthOfLongestSubstring(s) << endl;
    return 0;
}