rockywallet的博客

题目传送门 简单的哈希。 class Solution { public: int countCharacters(vector<string>& words, string chars) { int res = 0; int ch[26] = { 0 }; for (char c : chars) { ++ch[c - 'a']; } for (s...

5356. 矩阵中的幸运数 class Solution { public: vector<int> luckyNumbers (vector<vector<int>>& matrix) { vector<int> result; for(int i = 0; i < matrix.size();...

给定一个无序的整数数组，找到其中最长上升子序列的长度。题目传送门 示例: 输入: [10,9,2,5,3,7,101,18] 输出: 4 解释: 最长的上升子序列是 [2,3,7,101]，它的长度是 4。 简单的dp，状态转移方程，时间复杂度O(n^2) dp[i] = max(dp[i],dp[j]+1) class Solution { public: int lengthOfLI...

题目传送门 简单的递归题目。 class Solution { public: int ans = 0; int depth(TreeNode* rt) { if (rt == NULL) { return 0; } int l = depth(rt->left); int r = depth(rt->right); ans = max(ans, l...

5352. 生成每种字符都是奇数个的字符串 class Solution { public: string generateTheString(int n) { string result; if(n&1) { for(int i = 0; i < n;i++) { ...

题目传送门 class Solution { public: double findMaxAverage(vector<int>& nums, int k) { int sum = 0; for (int i = 0; i < k; i++) { sum += nums[i]; } double result = sum * 1.0 / k; ...

题目传送门 class Solution { public: int v[20] = {1,3,9,27,81,243,729,2187,6561,19683,59049,177147,531441,1594323,4782969,14348907,43046721,129140163,387420489,1162261467}; bool isPowerOfThree(int n...

题目传送门 class Solution { long long v[70] = { 1, 4, 9, 121, 484, 10201, 12321, 14641, 40804, 44944, 1002001, 1234321, 4008004, ...

题目传送门 class Solution { public: string longestCommonPrefix(vector<string>& strs) { string result = ""; if(strs.size() == 0) { return result; } for (int i = 0 ; i< strs[0]...

题目传送门 class Solution { public: map<char, int> m; char firstUniqChar(string s) { for(int i = 0; i < s.length();i++) { if(m.find(s[i]) == m.end()) { m[s[i]] = 1; } el...

class Solution { public: int reverse(int x) { bool minus = x < 0; if (x == -2147483648) { return 0; } x = x < 0 ? -x : x; char ch[15]; sprintf(ch,"%d", x); int length = s...

原题连接 We have two special characters. The first character can be represented by one bit 0. The second character can be represented by two bits (10 or 11). Now given a string represented by sev...

原题链接 Given a n x n matrix where each of the rows and columns are sorted in ascending order, find the kth smallest element in the matrix. Note that it is the kth smallest element in the sorted...

原题链接 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 ...

原题链接 Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), …, (an, bn) which makes sum of min(ai, bi) for all i from 1 to n as large ...

原题链接 You have a total of n coins that you want to form in a staircase shape, where every k-th row must have exactly k coins. Given n, find the total number of full staircase rows that can be ...

原题链接 Given two non-negative integers num1 and num2 represented as string, return the sum of num1 and num2. Note: The length of both num1 and num2 is &lt; 5100. Both num1 and num2 contains...

原题连接 Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has...

原题连接 Given two binary strings, return their sum (also a binary string). For example, a = “11” b = “1” Return “100”. 思路：模仿整数加法。 AC代码： class Solution { public: string addBinary(...