leetCode题解之Jewels and Stones

1、题目描述

2、分析

　　使用HashTable 是解决这种的好方法。

3、代码

 1 int numJewelsInStones(string J, string S) {
 2         map<char,int> m;
 3         for(char c : S)
 4             m[c]++;
 5
 6         int ans = 0;
 7         for( char c: J)
 8             ans += m[c];
 9         return ans;
10
11     }

原文地址：https://www.cnblogs.com/wangxiaoyong/p/8929669.html

时间： 2024-11-08 07:18:44

leetCode题解之Jewels and Stones的相关文章

codechef Jewels and Stones 题解

Soma is a fashionable girl. She absolutely loves shiny stones that she can put on as jewellery accessories. She has been collecting stones since her childhood - now she has become really good with identifying which ones are fake and which ones are no

（leetcode题解）Pascal&#39;s Triangle

Pascal's Triangle  Given numRows, generate the first numRows of Pascal's triangle. For example, given numRows = 5,Return [ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1] ] 题意实现一个杨辉三角. 这道题只要注意了边界条件应该很好实现出来,C++实现如下 vector<vector<int>> generate(int

[LeetCode]题解（python）：031-Next Permutation

题目来源 https://leetcode.com/problems/next-permutation/ Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possible, it must rearrange it as the lowest possible

leetcode 题解：Search in Rotated Sorted Array II （旋转已排序数组查找2）

题目: Follow up for "Search in Rotated Sorted Array":What if duplicates are allowed? Would this affect the run-time complexity? How and why? Write a function to determine if a given target is in the array. 说明: 1)和1比只是有重复的数字,整体仍采用二分查找 2)方法二 : 实现:  

[LeetCode 题解]: Binary Tree Preorder Traversal

Given a binary tree, return the preorder traversal of its nodes' values. For example:Given binary tree {1,#,2,3}, 1 2 / 3 return [1,2,3]. Note: Recursive solution is trivial, could you do it iteratively? 题意 先序遍历二叉树,递归的思路是普通的,能否用迭代呢? 非递归思路:<借助stack>

LeetCode题解

Reverse Words in a String 考虑几个特殊的情况1.若字符窜s="  "2.字符窜s=“a  b  d     e”3.字符窜s=“ a” class Solution { public: void reverseWords(string &s) { int i; int cas=0; string st[100]; s+=' '; for(i=0;i<s.size();i++) { if(i==0 && s[0]==' ') con

leetcode题解：Search in Rotated Sorted Array（旋转排序数组查找）

题目: Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2). You are given a target value to search. If found in the array return its index, otherwise return -1. You may assume no du

[LeetCode 题解]: Reverse Nodes in K-Groups

Given a linked list, reverse the nodes of a linked list k at a time and return its modified list. If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is. You may not alter the values in the nodes, only nod

[LeetCode 题解]: Linked List Cycle II

Given a linked list, return the node where the cycle begins. If there is no cycle, return null. Follow up:Can you solve it without using extra space? 题意: 给定一个链表,找到环起始的位置.如果环不存在,返回NULL. 分析: (1)首先要判断该链表是否有环.如果没有环,那么返回NULL. (2)其次,当已知环存在后,寻找环起始的位置. 思路: (