Algoritmlar va ma'lumotlar tuzilmalari

Kod yozishdan oldin o'ylash — eng tez optimizatsiya.

• Masalani tahlil qilish va savol berish
• Brute force'dan optimal yechimga
• Big-O: vaqt va xotira murakkabligi
• Constraints — masaladagi yashirin ishora
• Amortizatsiya tahlili: dynamic array misolida

Uyga vazifa — 15 ta masala

1. Two Sum
2. Contains Duplicate
3. Best Time to Buy and Sell Stock
4. Implement Queue using Stacks
5. Find Pivot Index
6. Plus One
7. Move Zeroes
8. Remove Duplicates from Sorted Array
9. Majority Element
10. Single Number
11. Missing Number
12. Squares of a Sorted Array
13. Intersection of Two Arrays II
14. Rotate Array
15. Product of Array Except Self

Ikkita sikl o'rniga bitta. Vaqt ham, asab ham tejaladi.

• Two Pointers: qarama-qarshi va fast-slow
• Sliding Window: fixed va variable
• Prefix Sum va Difference Array
• Kadane: maksimal subarray

Uyga vazifa — 15 ta masala

1. Valid Palindrome
2. Maximum Average Subarray I
3. Range Sum Query - Immutable
4. Two Sum II - Input Array Is Sorted
5. 3Sum
6. Container With Most Water
7. Corporate Flight Bookings
8. Longest Substring Without Repeating Characters
9. Minimum Size Subarray Sum
10. Permutation in String
11. Longest Repeating Character Replacement
12. Subarray Sum Equals K
13. Maximum Subarray
14. Maximum Product Subarray
15. Trapping Rain Water

«Shu yerda HashMap bor edi-ku!» demaslik uchun.

• HashMap va HashSet: ichkarida nima bor
• Frequency counting va anagram masalalari
• Two Sum va uning qarindoshlari
• Heap / Priority Queue: Top-K
• Kolliziyalar: chaining va open addressing

Uyga vazifa — 15 ta masala

1. Valid Anagram
2. First Unique Character in a String
3. Ransom Note
4. Isomorphic Strings
5. Word Pattern
6. Last Stone Weight
7. Design HashMap
8. Group Anagrams
9. Top K Frequent Elements
10. Kth Largest Element in an Array
11. Longest Consecutive Sequence
12. Find All Anagrams in a String
13. K Closest Points to Origin
14. Task Scheduler
15. Sort Characters By Frequency

Sortlab qo'ysangiz, masalaning yarmi o'zi yechiladi.

• Merge/Quick Sort va custom comparator
• Intervallar: merge, insert, kesishish
• Binary Search: lower va upper bound
• Javob bo'yicha Binary Search

Uyga vazifa — 15 ta masala

1. Binary Search
2. Search Insert Position
3. First Bad Version
4. Interval List Intersections
5. Merge Intervals
6. Insert Interval
7. Non-overlapping Intervals
8. Car Pooling
9. Find First and Last Position of Element in Sorted Array
10. Search in Rotated Sorted Array
11. Find Minimum in Rotated Sorted Array
12. Koko Eating Bananas
13. Capacity To Ship Packages Within D Days
14. Largest Number
15. Median of Two Sorted Arrays

Ko'rinishi oddiy — lekin aynan shu yerda ko'p xato qilinadi.

• Stack: qavslar va Monotonic Stack
• Queue va Deque: Sliding Window Max
• Linked List: reverse, merge, o'rta nuqta
• Floyd: toshbaqa va quyon algoritmi

Uyga vazifa — 15 ta masala

1. Valid Parentheses
2. Next Greater Element I
3. Number of Recent Calls
4. Reverse Linked List
5. Merge Two Sorted Lists
6. Middle of the Linked List
7. Linked List Cycle
8. Min Stack
9. Evaluate Reverse Polish Notation
10. Daily Temperatures
11. Linked List Cycle II
12. Remove Nth Node From End of List
13. Reorder List
14. Largest Rectangle in Histogram
15. Sliding Window Maximum

Rekursiyani tushunsangiz, daraxtlar o'zi yechiladi.

• Rekursiya va recursion tree
• Binary Tree va BST amallari
• Traversal: pre/in/post va level order
• Diameter, path sum va LCA
• Balanced BST: AVL va Red-Black g'oyasi

Uyga vazifa — 15 ta masala

1. Maximum Depth of Binary Tree
2. Invert Binary Tree
3. Symmetric Tree
4. Binary Tree Inorder Traversal
5. Diameter of Binary Tree
6. Path Sum
7. Balanced Binary Tree
8. Convert Sorted Array to Binary Search Tree
9. Balance a Binary Search Tree
10. Binary Tree Level Order Traversal
11. Path Sum II
12. Lowest Common Ancestor of a Binary Search Tree
13. Lowest Common Ancestor of a Binary Tree
14. Validate Binary Search Tree
15. Kth Smallest Element in a BST

Har qadamda eng yaxshisini tanlash — qachon ishlaydi, qachon aldaydi.

• Greedy yondashuv: qachon ishlaydi
• Interval scheduling va activity selection
• Huffman kodlash
• Exchange argument: greedy to'g'riligini isbotlash

Uyga vazifa — 15 ta masala

1. Assign Cookies
2. Lemonade Change
3. Maximum Units on a Truck
4. Jump Game
5. Jump Game II
6. Gas Station
7. Partition Labels
8. Minimum Number of Arrows to Burst Balloons
9. Queue Reconstruction by Height
10. Boats to Save People
11. Best Time to Buy and Sell Stock II
12. Reduce Array Size to The Half
13. Furthest Building You Can Reach
14. Split Array into Consecutive Subsequences
15. Candy

Xarita ham, do'stlar ro'yxati ham, kurs jadvali ham — graf.

• Graf tasvirlash: adjacency list
• BFS va DFS: qachon qaysi biri
• Grid masalalari: Islands va Flood Fill
• Topological Sort va Union-Find

Uyga vazifa — 15 ta masala

1. Flood Fill
2. Number of Islands
3. Max Area of Island
4. Rotting Oranges
5. 01 Matrix
6. Surrounded Regions
7. Pacific Atlantic Water Flow
8. Clone Graph
9. Course Schedule
10. Course Schedule II
11. Number of Provinces
12. Number of Operations to Make Network Connected
13. Redundant Connection
14. Accounts Merge
15. Word Ladder

Grafda shunchaki yurish emas — eng arzon yo'lni topish.

• Dijkstra: heap bilan eng qisqa yo'l
• Bellman-Ford va manfiy og'irliklar
• Floyd-Warshall: barcha juftliklar orasida
• MST: Kruskal va Prim

Uyga vazifa — 15 ta masala

1. Find if Path Exists in Graph
2. Network Delay Time
3. Cheapest Flights Within K Stops
4. Path With Minimum Effort
5. Find the City With the Smallest Number of Neighbors at a Threshold Distance
6. Min Cost to Connect All Points
7. Nearest Exit from Entrance in Maze
8. Shortest Path in Binary Matrix
9. Shortest Path with Alternating Colors
10. Number of Restricted Paths From First to Last Node
11. Number of Ways to Arrive at Destination
12. As Far from Land as Possible
13. Find Critical and Pseudo-Critical Edges in Minimum Spanning Tree
14. Swim in Rising Water
15. Minimum Cost to Make at Least One Valid Path in a Grid

Nomidan qo'rqmang: DP — bu eslab qolingan rekursiya.

• Backtracking: subsets va permutations
• N-Queens va Word Search
• Memoizatsiya → tabulatsiya
• 1D va 2D DP: house robber, unique paths

Uyga vazifa — 15 ta masala

1. Climbing Stairs
2. Min Cost Climbing Stairs
3. Subsets
4. Subsets II
5. Permutations
6. Permutations II
7. Combination Sum
8. Combination Sum II
9. Word Search
10. Letter Combinations of a Phone Number
11. Palindrome Partitioning
12. House Robber
13. House Robber II
14. Unique Paths
15. N-Queens

DP asoslarini o'zlashtirdingiz — endi haqiqiy masalalar.

• Knapsack va uning variantlari
• LIS: eng uzun o'suvchi ketma-ketlik
• Daraxtlarda DP
• Bitmask DP
• Satrlarda DP: LCS va edit distance
• State machine DP: holatlar bilan ishlash

Uyga vazifa — 15 ta masala

1. Is Subsequence
2. Partition Equal Subset Sum
3. Target Sum
4. Coin Change
5. Coin Change II
6. Longest Increasing Subsequence
7. Longest Common Subsequence
8. Edit Distance
9. House Robber III
10. Best Time to Buy and Sell Stock with Cooldown
11. Partition to K Equal Sum Subsets
12. Longest Palindromic Subsequence
13. Russian Doll Envelopes
14. Binary Tree Maximum Path Sum
15. Shortest Path Visiting All Nodes

Satrlarning o'z strukturasi va o'z algoritmlari bor.

• Trie: qurish, qidirish va prefiks
• Rabin-Karp: hash bilan qidirish
• KMP: prefix funksiya
• Palindrom va satr masalalari

Uyga vazifa — 15 ta masala

1. Repeated Substring Pattern
2. Find the Index of the First Occurrence in a String
3. Valid Palindrome II
4. String Matching in an Array
5. Implement Trie (Prefix Tree)
6. Design Add and Search Words Data Structure
7. Replace Words
8. Longest Word in Dictionary
9. Maximum XOR of Two Numbers in an Array
10. Longest Palindromic Substring
11. Palindromic Substrings
12. Repeated String Match
13. Word Search II
14. Shortest Palindrome
15. Longest Happy Prefix