Leecode 0076. Minimum Window Substring
76. Minimum Window Substring题目Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n). Example: 12Input: S = "ADOBECODEBANC", T = "ABC"Output: "BANC" Note: If there is no such window in S that covers all characters in T, return the empty string "". If there is such window, you are guaranteed that there will always be only one unique minimum window in S. 题目大意给定一个源字符串 s，再给一个字符串...
Leecode 0904. Fruit Into Baskets
904. Fruit Into Baskets题目In a row of trees, the i-th tree produces fruit with type tree[i]. You start at any tree of your choice, then repeatedly perform the following steps: Add one piece of fruit from this tree to your baskets. If you cannot, stop. Move to the next tree to the right of the current tree. If there is no tree to the right, stop. Note that you do not have any choice after the initial choice of starting tree: you must perform step 1, then step 2, then back to step 1, then...
Leecode 0012. Integer to Roman
12. Integer to Roman题目Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. 12345678Symbol ValueI 1V 5X 10L 50C 100D 500M 1000 For example, 2 is written as II in Roman numeral, just two one's added together. 12 is written as XII, which is simply X + II. The number 27 is written as XXVII, which is XX + V + II. Roman numerals are usually written largest to smallest from...
Leecode 0105. Construct Binary Tree from Preorder and Inorder Traversal
105. Construct Binary Tree from Preorder and Inorder Traversal题目Given preorder and inorder traversal of a tree, construct the binary tree. **Note:**You may assume that duplicates do not exist in the tree. For example, given preorder = [3,9,20,15,7] inorder = [9,3,15,20,7] Return the following binary tree: 3 / \ 9 20 / \ 15 7 题目大意根据一棵树的前序遍历与中序遍历构造二叉树。 注意:你可以假设树中没有重复的元素。 解题思路 inorder_map：用于快速查找中序遍历中元素对应的索引，时间复杂度 O...
Leecode 0017. Letter Combinations of a Phone Number
17. Letter Combinations of a Phone Number题目Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the telephone buttons) is given below. Note that 1 does not map to any letters. Example: 12Input: "23"Output: ["ad", "ae", "af", "bd", "be", "bf", "cd", "ce", "cf"]. Note: Although...
Leecode 0073. Set Matrix Zeroes
73. Set Matrix Zeroes题目Given an *m* x *n* matrix. If an element is 0, set its entire row and column to 0. Do it in-place. Follow up: A straight forward solution using O(mn) space is probably a bad idea. A simple improvement uses O(m + n) space, but still not the best solution. Could you devise a constant space solution? Example 1: 12Input: matrix = [[1,1,1],[1,0,1],[1,1,1]]Output: [[1,0,1],[0,0,0],[1,0,1]] Example 2: 12Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]]Output:...
