# LeetCode Summer Plan — Yuvaraj_001
**May 24 → July 9, 2026 | 47 days | 1 problem/day | Easy → Hard**

Aligned to BCSE204L: Design and Analysis of Algorithms (VIT Chennai, Sem 5)

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## Phase 1 — Binary Search + Greedy (Days 1–7)
*DAA Module 1: Greedy Techniques, Divide and Conquer*
*Build confidence fast. Binary search is in every hard problem.*

| Day | Date | Problem | Difficulty | DAA Link |
|-----|------|---------|------------|----------|
| 1 | May 24 | [Binary Search](https://leetcode.com/problems/binary-search/) | 🟢 Easy | D&C foundation |
| 2 | May 25 | [First Bad Version](https://leetcode.com/problems/first-bad-version/) | 🟢 Easy | Binary search on answer |
| 3 | May 26 | [Search Insert Position](https://leetcode.com/problems/search-insert-position/) | 🟢 Easy | Binary search variant |
| 4 | May 27 | [Assign Cookies](https://leetcode.com/problems/assign-cookies/) | 🟢 Easy | Greedy: Module 1 |
| 5 | May 28 | [Lemonade Change](https://leetcode.com/problems/lemonade-change/) | 🟢 Easy | Greedy |
| 6 | May 29 | [Best Time to Buy and Sell Stock](https://leetcode.com/problems/best-time-to-buy-and-sell-stock/) | 🟢 Easy | Greedy |
| 7 | May 30 | [Maximum Subarray](https://leetcode.com/problems/maximum-subarray/) | 🟡 Medium | D&C: Kadane's — in DAA Module 1 |

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## Phase 2 — Trees (Days 8–14)
*DAA Module 1 (D&C on trees) + Module 4 (graph algorithms build on trees)*
*Your Trees count is 0. Fix that this week.*

| Day | Date | Problem | Difficulty | DAA Link |
|-----|------|---------|------------|----------|
| 8 | May 31 | [Maximum Depth of Binary Tree](https://leetcode.com/problems/maximum-depth-of-binary-tree/) | 🟢 Easy | Recursion, D&C |
| 9 | Jun 1 | [Symmetric Tree](https://leetcode.com/problems/symmetric-tree/) | 🟢 Easy | Tree traversal |
| 10 | Jun 2 | [Invert Binary Tree](https://leetcode.com/problems/invert-binary-tree/) | 🟢 Easy | Recursion |
| 11 | Jun 3 | [Binary Tree Inorder Traversal](https://leetcode.com/problems/binary-tree-inorder-traversal/) | 🟢 Easy | Core traversal |
| 12 | Jun 4 | [Validate Binary Search Tree](https://leetcode.com/problems/validate-binary-search-tree/) | 🟡 Medium | BST property proof |
| 13 | Jun 5 | [Binary Tree Level Order Traversal](https://leetcode.com/problems/binary-tree-level-order-traversal/) | 🟡 Medium | BFS on trees |
| 14 | Jun 6 | [Lowest Common Ancestor of a Binary Tree](https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/) | 🟡 Medium | D&C on trees |

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## Phase 3 — Dynamic Programming Part 1 (Days 15–21)
*DAA Module 2: Assembly Line, LCS, 0-1 Knapsack — these are the exact exam problems*

| Day | Date | Problem | Difficulty | DAA Link |
|-----|------|---------|------------|----------|
| 15 | Jun 7 | [Climbing Stairs](https://leetcode.com/problems/climbing-stairs/) | 🟢 Easy | DP warmup, Fibonacci base |
| 16 | Jun 8 | [House Robber](https://leetcode.com/problems/house-robber/) | 🟡 Medium | 1D DP — Assembly Line style |
| 17 | Jun 9 | [Longest Increasing Subsequence](https://leetcode.com/problems/longest-increasing-subsequence/) | 🟡 Medium | Classic DP |
| 18 | Jun 10 | [Coin Change](https://leetcode.com/problems/coin-change/) | 🟡 Medium | DP: why Greedy fails here |
| 19 | Jun 11 | [Unique Paths](https://leetcode.com/problems/unique-paths/) | 🟡 Medium | 2D DP grid |
| 20 | Jun 12 | [Partition Equal Subset Sum](https://leetcode.com/problems/partition-equal-subset-sum/) | 🟡 Medium | 0-1 Knapsack — DAA Module 2 directly |
| 21 | Jun 13 | [Longest Common Subsequence](https://leetcode.com/problems/longest-common-subsequence/) | 🟡 Medium | LCS — DAA Module 2 exactly |

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## Phase 4 — DP Part 2 + Backtracking (Days 22–28)
*DAA Module 2: Matrix Chain Multiplication, N-Queens, Subset Sum*

| Day | Date | Problem | Difficulty | DAA Link |
|-----|------|---------|------------|----------|
| 22 | Jun 14 | [Edit Distance](https://leetcode.com/problems/edit-distance/) | 🟡 Medium | 2D DP, used in KMP context |
| 23 | Jun 15 | [Burst Balloons](https://leetcode.com/problems/burst-balloons/) | 🔴 Hard | Matrix Chain Multiplication pattern — DAA Module 2 |
| 24 | Jun 16 | [Subsets](https://leetcode.com/problems/subsets/) | 🟡 Medium | Backtracking: Subset Sum — DAA Module 2 |
| 25 | Jun 17 | [Combination Sum](https://leetcode.com/problems/combination-sum/) | 🟡 Medium | Backtracking |
| 26 | Jun 18 | [Permutations](https://leetcode.com/problems/permutations/) | 🟡 Medium | Backtracking |
| 27 | Jun 19 | [Letter Combinations of a Phone Number](https://leetcode.com/problems/letter-combinations-of-a-phone-number/) | 🟡 Medium | Backtracking |
| 28 | Jun 20 | [N-Queens](https://leetcode.com/problems/n-queens/) | 🔴 Hard | N-Queens — DAA Module 2 exactly |

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## Phase 5 — Graphs Part 1: BFS/DFS + Topological Sort (Days 29–35)
*DAA Module 4: Graph algorithms foundation before Bellman-Ford + Floyd-Warshall*
*Your Graphs count is 0. This fixes it.*

| Day | Date | Problem | Difficulty | DAA Link |
|-----|------|---------|------------|----------|
| 29 | Jun 21 | [Number of Islands](https://leetcode.com/problems/number-of-islands/) | 🟡 Medium | DFS/BFS — Module 4 foundation |
| 30 | Jun 22 | [Rotting Oranges](https://leetcode.com/problems/rotting-oranges/) | 🟡 Medium | BFS multi-source |
| 31 | Jun 23 | [Clone Graph](https://leetcode.com/problems/clone-graph/) | 🟡 Medium | Graph traversal |
| 32 | Jun 24 | [Course Schedule](https://leetcode.com/problems/course-schedule/) | 🟡 Medium | Topological sort — DAA Module 4 |
| 33 | Jun 25 | [Pacific Atlantic Water Flow](https://leetcode.com/problems/pacific-atlantic-water-flow/) | 🟡 Medium | DFS from multiple sources |
| 34 | Jun 26 | [Shortest Path in Binary Matrix](https://leetcode.com/problems/shortest-path-in-binary-matrix/) | 🟡 Medium | BFS shortest path |
| 35 | Jun 27 | [Network Delay Time](https://leetcode.com/problems/network-delay-time/) | 🟡 Medium | Dijkstra / Bellman-Ford — DAA Module 4 exactly |

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## Phase 6 — Graphs Part 2: Shortest Paths + String Matching (Days 36–42)
*DAA Module 4: Floyd-Warshall, Network Flows | Module 3: Naïve matching, KMP, Rabin-Karp*

| Day | Date | Problem | Difficulty | DAA Link |
|-----|------|---------|------------|----------|
| 36 | Jun 28 | [Find the City With the Smallest Number of Neighbors](https://leetcode.com/problems/find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance/) | 🟡 Medium | Floyd-Warshall — DAA Module 4 exactly |
| 37 | Jun 29 | [Word Ladder](https://leetcode.com/problems/word-ladder/) | 🔴 Hard | BFS + graph modelling |
| 38 | Jun 30 | [Find the Index of the First Occurrence in a String](https://leetcode.com/problems/find-the-index-of-the-first-occurrence-in-a-string/) | 🟢 Easy | Naïve string matching — DAA Module 3 |
| 39 | Jul 1 | [Longest Palindromic Substring](https://leetcode.com/problems/longest-palindromic-substring/) | 🟡 Medium | String DP |
| 40 | Jul 2 | [Minimum Window Substring](https://leetcode.com/problems/minimum-window-substring/) | 🔴 Hard | Sliding window on strings |
| 41 | Jul 3 | [Koko Eating Bananas](https://leetcode.com/problems/koko-eating-bananas/) | 🟡 Medium | Binary search on answer |
| 42 | Jul 4 | [Search in Rotated Sorted Array](https://leetcode.com/problems/search-in-rotated-sorted-array/) | 🟡 Medium | Binary search variant |

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## Phase 7 — Hard Finishers (Days 43–47)
*DAA: Approximation, NP-hard concepts translated to LeetCode Hard problems*

| Day | Date | Problem | Difficulty | DAA Link |
|-----|------|---------|------------|----------|
| 43 | Jul 5 | [Jump Game II](https://leetcode.com/problems/jump-game-ii/) | 🟡 Medium | Greedy advanced |
| 44 | Jul 6 | [Maximum Profit in Job Scheduling](https://leetcode.com/problems/maximum-profit-in-job-scheduling/) | 🔴 Hard | Job scheduling — DAA Module 2 (TSP/scheduling) |
| 45 | Jul 7 | [Critical Connections in a Network](https://leetcode.com/problems/critical-connections-in-a-network/) | 🔴 Hard | Bridges/Tarjan — advanced graph |
| 46 | Jul 8 | [Sudoku Solver](https://leetcode.com/problems/sudoku-solver/) | 🔴 Hard | Backtracking mastery |
| 47 | Jul 9 | [Median of Two Sorted Arrays](https://leetcode.com/problems/median-of-two-sorted-arrays/) | 🔴 Hard | D&C — DAA Module 1 exactly |

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## Coverage Summary

| DAA Module | Topics | Days |
|---|---|---|
| Module 1: Greedy + D&C | Binary Search, Greedy, Maximum Subarray, Median of 2 Arrays | 1–7, 43, 47 |
| Module 2: DP + Backtracking | Climbing Stairs → LCS → N-Queens → Matrix Chain | 15–28 |
| Module 3: String Matching | Naïve matching → Sliding Window → String DP | 38–40 |
| Module 4: Graph Algorithms | BFS/DFS → Bellman-Ford → Floyd-Warshall → Network Flow | 29–37 |
| Bonus | Advanced Binary Search, Hard backtracking | 41–46 |

## Difficulty Ramp

```
Days 1–11:   🟢🟢🟢🟢🟢🟢🟡🟢🟢🟢🟢   (Mostly Easy)
Days 12–22:  🟡🟡🟡🟢🟡🟡🟡🟡🟡🟡🟡   (All Medium)
Days 23–37:  🔴🟡🟡🟡🟡🟡🟡🔴🟡🟡🟡🟡🟡🟡🟡   (Medium + first Hards)
Days 38–47:  🟢🟡🔴🟡🟡🟡🔴🔴🔴🔴   (Hard closer)
```

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*Generated: 2026-05-24 | Profile: leetcode.com/u/Yuvaraj_001*