Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each number in C may only be used once in the combination. Note: All numbers (including target) will be posi…
Write a program to solve a Sudoku puzzle by filling the empty cells. Empty cells are indicated by the character '.'. You may assume that there will be only one unique solution. A sudoku puzzle... ...and its solution numbers marked in red. 题意分析: 本题是要解…
Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order. You may assume no duplicates in the array. Here are few examples.[1,3,5,6], 5 → 2[1,3,5,6], 2 →…
Given a string s, partition s such that every substring of the partition is a palindrome. Return the minimum cuts needed for a palindrome partitioning of s. For example, given s = "aab",Return 1 since the palindrome partitioning ["aa",…
Given a string s, partition s such that every substring of the partition is a palindrome. Return all possible palindrome partitioning of s. For example, given s = "aab",Return [ ["aa","b"], ["a","a","…
[Q7] 把数倒过来 Given a 32-bit signed integer, reverse digits of an integer. Example 1: Input: 123 Output: 321 Example 2: Input: -123 Output: -321 Example 3: Input: 120 Output: 21 Solution: https://leetcode.com/problems/reverse-integer/discuss/229800/Pyt…
Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward. Example 1: Input: 121 Output: true Example 2: Input: -121 Output: false Explanat…
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example,"A man, a plan, a canal: Panama" is a palindrome."race a car" is not a palindrome. Note:Have you consider that th…
[Q19] Given a linked list, remove the n-th node from the end of list and return its head. Example: Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the end, the linked list becomes 1->2->3->5. Note: Giv…
[Q10] Given an input string (s) and a pattern (p), implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of the preceding element. The matching should cover the entire input str…
[Q1] Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. Example: Given nums = [2, 7, 11…
[Q13] Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. Symbol Value I 1 V 5 X 10 L 50 C 100 D 500 M 1000 For example, two is written as II in Roman numeral, just two one's added together. Twelve is written as, XII, w…
The count-and-say sequence is the sequence of integers beginning as follows:1, 11, 21, 1211, 111221, ... 1 is read off as "one 1" or 11.11 is read off as "two 1s" or 21.21 is read off as "one 2, then one 1" or 1211. Given an…
题目: There are N gas stations along a circular route, where the amount of gas at station i is gas[i]. You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from station i to its next station (i+1). You begin the journey with…
Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in-place. Example 1: Input: [ [1,1,1], [1,0,1], [1,1,1] ] Output: [ [1,0,1], [0,0,0], [1,0,1] ] Example 2: Input: [ [0,1,2,0], [3,4,5,2], [1,3,1,5]…
[Q4] There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). You may assume nums1 and nums2 cannot be both empty. Example 1: nums1 = […
Given two words (start and end), and a dictionary, find all shortest transformation sequence(s) from start to end, such that: Only one letter can be changed at a time Each intermediate word must exist in the dictionary For example, Given:start = "hit…
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). For example,S = "ADOBECODEBANC"T = "ABC" Minimum window is "BANC". Note:If there is no such window i…
Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively. Below is one possible representation of s1 = "great": great / \ gr eat / \ / \ g r e at / \ a t To scramble the string, we may ch…
Sort a linked list in O(n log n) time using constant space complexity. 题解:实现一个链表的归并排序即可.主要分为三部分: 1.找到中点并返回的函数findMiddle; 2.归并函数merge; 3.排序函数sortList. 数组的findMiddle函数非常容易实现,链表就有一点tricky了.首先设置两个指针,一个slow初始化为head,一个fast初始化为head.next,然后slow一次走一步,fast一次走两…
Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one and sell one share of the stock multiple times). Ho…
What if the given tree could be any binary tree? Would your previous solution still work? Note: You may only use constant extra space. For example,Given the following binary tree, 1 / \ 2 3 / \ \ 4 5 7 After calling your function, the tree should loo…
LeetCode第58题: Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string. If the last word does not exist, return 0. Note: A word is defined as a character sequence consists of…
LeetCode第28题 Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Input: haystack = "hello", needle = "ll" Output: 2 Example 2: Input: haystack = "aaaaa", needle…
Given two numbers represented as strings, return multiplication of the numbers as a string. Note: The numbers can be arbitrarily large and are non-negative. 题意分析: 本题是求两个用string表示的非负大数的乘积,乘数可以是任意大小. 解答: 可以用一个临时List表示乘积的每一位,然后对两个乘数每一位两两相乘,并将结果填到相应的List…
Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it is able to trap after raining. For example, Given [0,1,0,2,1,0,1,3,2,1,2,1], return 6. The above elevation map is represented by a…
Given an unsorted integer array, find the first missing positive integer. For example,Given [1,2,0] return 3,and [3,4,-1,1] return 2. Your algorithm should run in O(n) time and uses constant space. 题意分析: 本题是给一个整数的数组,让你按顺序找出第一个缺失的正整数.也就是说从1开始查找,找到了1再找…
Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same repeated number may be chosen from C unlimited number of times. Note: All numbers (including target) will…
