LeetCode难度和面试频率（转）

转自：http://www.cnblogs.com/ywl925/p/3507945.html

 

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 Data Structure

 

 Algorithms

 

 1Two Sum25arraysort     setTwo Pointers 2Add Two Numbers34linked listTwo Pointers      Math 3Longest Substring Without Repeating Characters32stringTwo Pointers     hashtable  4Median of Two Sorted Arrays53arrayBinary Search 5Longest Palindromic Substring42string  6ZigZag Conversion31string  7Reverse Integer23 Math 8String to Integer (atoi)25stringMath 9Palindrome Number22 Math 10Regular Expression Matching53stringRecursion      DP 11Container With Most Water32arrayTwo Pointers 12Integer to Roman34 Math 13Roman to Integer24 Math 14Longest Common Prefix21string  153Sum35arrayTwo Pointers 163Sum Closest31arrayTwo Pointers 17Letter Combinations of a Phone Number33stringDFS 184Sum32array  19Remove Nth Node From End of List23linked listTwo Pointers 20Valid Parentheses25stringStack 21Merge Two Sorted Lists25linked listsort      Two Pointers      merge 22Generate Parentheses34stringDFS 23Merge k Sorted Lists34linked listsort     heapTwo Pointers      merge 24Swap Nodes in Pairs24linked list  25Reverse Nodes in k-Group42linked listRecursion      Two Pointers 26Remove Duplicates from Sorted Array13arrayTwo Pointers 27Remove Element14arrayTwo Pointers 28Implement strStr()45stringTwo Pointers      KMP      rolling hash 29Divide Two Integers43 Binary Search      Math 30Substring with Concatenation of All Words31stringTwo Pointers 31Next Permutation52arraypermutation 32Longest Valid Parentheses41stringDP 33Search in Rotated Sorted Array43arrayBinary Search 34Search for a Range43arrayBinary Search 35Search Insert Position22array  36Valid Sudoku22array  37Sudoku Solver42arrayDFS 38Count and Say22stringTwo Pointers 39Combination Sum33arraycombination 40Combination Sum II42arraycombination 41First Missing Positive52arraysort 42Trapping Rain Water42arrayTwo Pointers      Stack 43Multiply Strings43stringTwo Pointers      Math 44Wildcard Matching53stringRecursion      DP      greedy 45Jump Game II42array  46Permutations34arraypermutation 47Permutations II42arraypermutation 48Rotate Image42array  49Anagrams34string      hashtable  50Pow(x, n)35 Binary Search      Math 51N-Queens43arrayDFS 52N-Queens II43arrayDFS 53Maximum Subarray33arrayDP 54Spiral Matrix42array  55Jump Game32array  56Merge Intervals45arraysort     linked listmerge     red-black tree  57Insert Interval45arraysort     linked listmerge     red-black tree  58Length of Last Word11string  59Spiral Matrix II32array  60Permutation Sequence51 permutation      Math 61Rotate List32linked listTwo Pointers 62Unique Paths23arrayDP 63Unique Paths II33arrayDP 64Minimum Path Sum33arrayDP 65Valid Number25stringMath 66Plus One12arrayMath 67Add Binary24stringTwo Pointers      Math 68Text Justification42string  69Sqrt(x)44 Binary Search 70Climbing Stairs25 DP 71Simplify Path31stringStack 72Edit Distance43stringDP 73Set Matrix Zeroes35array  74Search a 2D Matrix33arrayBinary Search 75Sort Colors42arraysort      Two Pointers 76Minimum Window Substring42stringTwo Pointers 77Combinations34 combination 78Subsets34arrayRecursion      combination 79Word Search34arrayDFS 80Remove Duplicates from Sorted Array II22arrayTwo Pointers 81Search in Rotated Sorted Array II53arrayBinary Search 82Remove Duplicates from Sorted List II33linked listRecursion      Two Pointers 83Remove Duplicates from Sorted List13linked list  84Largest Rectangle in Histogram52arrayStack 85Maximal Rectangle51arrayDP      Stack 86Partition List33linked listTwo Pointers 87Scramble String52stringRecursion      DP 88Merge Sorted Array25arrayTwo Pointers      merge 89Gray Code42 combination 90Subsets II42arrayRecursion      combination 91Decode Ways34stringRecursion      DP 92Reverse Linked List II32linked listTwo Pointers 93Restore IP Addresses33stringDFS 94Binary Tree Inorder Traversal43treeRecursion     hashtablemorris      Stack 95Unique Binary Search Trees II41treeDP      DFS 96Unique Binary Search Trees31treeDP 97Interleaving String52stringRecursion      DP 98Validate Binary Search Tree35treeDFS 99Recover Binary Search Tree42treeDFS 100Same Tree11treeDFS 101Symmetric Tree12treeDFS 102Binary Tree Level Order Traversal34treeBFS 103Binary Tree Zigzag Level Order Traversal43queueBFS     treeStack 104Maximum Depth of Binary Tree11treeDFS 105Construct Binary Tree from Preorder and Inorder Tr33arrayDFS     tree  106Construct Binary Tree from Inorder and Postorder T33arrayDFS     tree  107Binary Tree Level Order Traversal II31treeBFS 108Convert Sorted Array to Binary Search Tree23treeDFS 109Convert Sorted List to Binary Search Tree43linked listRecursion      Two Pointers 110Balanced Binary Tree12treeDFS 111Minimum Depth of Binary Tree11treeDFS 112Path Sum13treeDFS 113Path Sum II22treeDFS 114Flatten Binary Tree to Linked List33treeRecursion      Stack 115Distinct Subsequences42stringDP 116Populating Next Right Pointers in Each Node33treeDFS 117Populating Next Right Pointers in Each Node II42treeDFS 118Pascal's Triangle21array  119Pascal's Triangle II21array  120Triangle31arrayDP 121Best Time to Buy and Sell Stock21arrayDP 122Best Time to Buy and Sell Stock II31arraygreedy 123Best Time to Buy and Sell Stock III41arrayDP 124Binary Tree Maximum Path Sum42treeDFS 125Valid Palindrome25stringTwo Pointers 126Word Ladder II11   127Word Ladder35graphBFS      shortest path 128Longest Consecutive Sequence43array  129Sum Root to Leaf Numbers24treeDFS 130Surrounded Regions43arrayBFS      DFS 131Palindrome Partitioning34stringDFS 132Palindrome Partitioning II43stringDP