Patching ArrayGiven a sorted positive integer array nums and an integer n, add/patch elements to the array such that any number in range [1, n] inclusive can be formed by the sum of some elements in the array. Return the minimum number of patches required.Example 1:nums = [1, 3], n = 6Return 1.Combinations of nums are [1], [3], [1,3], which form possible sums of: 1, 3, 4.Now if we add/patch 2 to n...
Add and Search Word - Data structure designDesign a data structure that supports the following two operations:void addWord(word) bool search(word) search(word) can search a literal word or a regular expression string containing only letters a-z or .. A . means it can represent any one letter.For example:addWord("bad") addWord("dad") addWord("mad") search("pad") -> false search("bad") -> true searc...
【082-Remove Duplicates from Sorted List II（排序链表中删除重复元素II）】【LeetCode-面试算法经典-Java实现】【所有题目目录索引】原题 Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. For example, Given 1->2->3->3->4->4->5, return 1->2->5. Given 1->1->1->2->3, return 2->3. 题目大意 给定一个排好序的单链表，删除所有重复...
【JavaScript】Leetcode每日一题-组合总和4【题目描述】给你一个由 不同 整数组成的数组 nums ，和一个目标整数 target 。请你从 nums 中找出并返回总和为 target 的元素组合的个数。题目数据保证答案符合 32 位整数范围。示例1：输入：nums = [1,2,3], target = 4 输出：7 解释： 所有可能的组合为： (1, 1, 1, 1) (1, 1, 2) (1, 2, 1) (1, 3) (2, 1, 1) (2, 2) (3, 1) 请注意，顺序不同的序列被视作不同的组合。 示例2：输入：nu...
A message containing letters from A-Z is being encoded to numbers using the following mapping:‘A‘ -> 1 ‘B‘ -> 2 ... ‘Z‘ -> 26Given a non-empty string containing only digits, determine the total number of ways to decode it.Example 1:Input: "12" Output: 2 Explanation: It could be decoded as "AB" (1 2) or "L" (12). Example 2:Input: "226" Output: 3 Explanation: It could be decoded as "BZ" (2 ...
题目：Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive.For example, given the range [5, 7], you should return 4. 思路：开始一位一位做的TLE了，这是网上很简洁很好的一个方法。 很容易理解，因为是2进制，不一样则相与为0，如果第i位一样，i-1位不一样，那么m、n肯定不是相连的，那么其中必然会有一个数字第i位不一样。代码：publicclass Sol...
解题思路分析：该题是在一个整数数组中找到一个和最大的连续子数组，并返回和值。那么如何找到一个和最大的连续子数组呢？我们知道，这肯定需要遍历数组才行；好，那我们就开始遍历数组。首先，我们初始化最大和 sum 和当前和 currSum，对于 currSum，如果它小于0，我们就将数组中下一值赋给它；否则就将数组中下一值与其相加。然后，我们取当前 sum 和 currSum 的最大值即可。代码实现：var maxSubArray = function(nums) {//首先...
题目难度：Easy题目：Given a sorted array, remove the duplicates in-place such that each element appear only once and return the new length.Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.翻译：给定一个排好序的数组后，删除重复的元素，这样每个元素只出现一次，并返回新的长度。不要新建另一个数组分配额外的空间，只能通过修改原有...
题目： Given a binary tree and a sum, find all root-to-leaf paths where each path‘s sum equals the given sum. For example: Given the below binary tree and sum = 22,5/ 4 8/ / 11 13 4/ \ / 7 2 5 1return[[5,4,11,2],[5,8,4,5] ]题解： 这道题除了要判断是否有这样的一个path sum，还需要把所有的都可能性结果都返回，所以就用传统的DFS递归解决子问题。代码如下： 1 ...
题目在这里: https://leetcode.com/problems/trapping-rain-water/[标签] Array; Stack; Two Pointers这个题我感觉很难，我自己是完全不会。下面贴的是别人想到的好方法，自己适当做了些简单调整。我觉得，这个解法非常巧妙的使用了双向的 two pointers。用到的变量有左右两个指针，一个在最左边，一个在最右边，然后两个一起往中间走。在走的时候维护两个变量，left barrier 和 right barrier，即左边的挡板和右边的挡板。用例子说...
最先想到的两重for循环，超时，输入的数组很大，一整个页面的数，人直接傻了class Solution {public int numPairsDivisibleBy60(int[] time) {int count = 0;for(int i=0;i<time.length - 1;i++){for(int j=i+1;j<time.length;j++){if((time[i] + time[j]) % 60 == 0){count++;}}}return count;} } 接下来运用余数的思想。一个数除以60的余数为0~59，建立一个数组remainder保存余数出现的次数。 先不考虑余数为0和30的情况。 剩下的...
Given two binary strings, return their sum (also a binary string). For example, a = "11" b = "1" Return "100". 解题思路：JAVA实现如下：static public String addBinary(String a, String b) {if (a.length() < b.length()) {String temp = a;a = b;b = temp;}boolean carry = false;StringBuilder sb = new StringBuilder(a);for (int i = 0; i < b.length(); i++) {if (b.charAt(b.length() - 1 - i) == ‘0‘) {if (sb....
Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position. Determine if you are able to reach the last index. For example: A = [2,3,1,1,4], return true. A = [3,2,1,0,4], return false. 这道题的巧妙之处在于，每一个值可以跳“值”大小步数。所以我们的思路如下： 1.记录到现在为止能跳...
Given two words (beginWord and endWord), and a dictionary‘s word list, find the length of shortest transformation sequence from beginWord to endWord, such that:Only one letter can be changed at a time.Each transformed word must exist in the word list. Note that beginWord is not a transformed word.Note:Return 0 if there is no such transformation sequence.All words have the same length.All words co...
Number of Digit OneGiven an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.For example:Given n = 13,Return 6, because digit 1 occurred in the following numbers: 1, 10, 11, 12, 13. 数学题，真是为难了数学拙计的我了。递归分治，拿8192举栗子：把8192拆成：1-999 -> 递归(999)1000-1999 -> 1000个1 + 递归(999)2001-2999 -> 递归(999)..8000-8192 ->...