自己的学习笔记

LeetCode 345 Reverse Vowels of a String//vowels : a e i o u#include <string>using namespace std;class Solution {public: bool isVowel(char s){ if (s == 'a' || s == 'e' || s == 'i' || s == '

LeetCode 541 reverse string 2#include <string>using namespace std;class Solution {public: string reverseStr(string s, int k) { int i = 0; while (i < s.length()) {

LeetCode 387 First Unique Character in a String#include <string>#include <vector>using namespace std;class Solution {public: int firstUniqChar(string s) { vector <int> abc(26);//长度26的ve

LeetCode 344 Reverse String#include <string>using namespace std;class Solution {public: string reverseString(string s) { int i = 0; int j = s.size() - 1; while (i < j)

LeetCode 205 Isomorphic Strings#include <string>using namespace std;class Solution {public: bool isIsomorphic(string s, string t) { char s_t[128] = { 0 };//串s到t的映射，最多128个，因为ascii码

LeetCode 167 Two Sum 2-Input array is sorted#include <vector>using namespace std;class Solution {public: vector<int> twoSum(vector<int>& numbers, int target) { vector<int> result;

LeetCode 26 Remove Duplicates from Sorted Array#include <vector>#include <algorithm>//unique函数，stlusing namespace std;class Solution {public: int removeDuplicates(vector<int>& nums) { n

Leetcode 9 Palindrome Number 回文数#include <sstream>using namespace std;class Solution {public: bool isPalindrome(int x) { stringstream sstr; sstr << x; string s;

Leetcode 7 Reverse Integer#include <sstream>#include <string>using namespace std;class Solution {public: int reverse(int x) { int y = 0; while(x != 0){ if (y > INT_M

Leetcode 1 Two Sum#include <vector>using namespace std;class Solution {public: vector<int> twoSum(vector<int>& nums, int target) { vector<int> result; int length = nums.size();

Leetcode 125 Valid Palindrome#include <string>#include <algorithm>using namespace std;class Solution {public: bool isPalindrome(string s) { if (s.empty()) return true;

Leetcode 383 Ransom Note#include <string>#include <vector>using namespace std;class Solution {public: bool canConstruct(string ransomNote, string magazine) { vector <int> ransomNoteFreq

Leetcode 434 Number of Segments in a String#include <string>using namespace std;class Solution {public: int countSegments(string s) { if (s.length() == 0) return 0; in

Leetcode 448 Find All Numbers Disappeared in an Array#include <vector>using namespace std;class Solution {public: vector<int> findDisappearedNumbers(vector<int>& nums) { vector<int> disap

Leetcode 520 Detect Capital#include <string>using namespace std;class Solution {public: bool detectCapitalUse(string word) { if (word.length() <= 1) return true; bool

Leetcode 551 Student Attendance Record I#include <string>using namespace std;class Solution {public: bool checkRecord(string s) { //两个以上连续的L也就是存在LLL int aFreq = 0; int len

Leetcode 557 Reverse Words in a String IIIclass Solution {public: string reverseWords(string s) { int i = 0; int length = s.length(); int left = 0; int right = 0;//

Leetcode 581 Shortest Unsorted Continuous Subarray#include <vector>#include <algorithm>using namespace std;//多开一个vector，从前从后比较从哪儿开始元素不一样class Solution {public: int findUnsortedSubarray(vector<

Leetcode 624 Maximum Distance in Arrays#include <vector>#include <windef.h>//max函数using namespace std;class Solution {public: int maxDistance(vector<vector<int>>& arrays) { int distance

Leetcode 231 Power of Two#include <math.h>using namespace std;class Solution {public: bool isPowerOfTwo(int n) { //如果n&(n-1)是0，则n是2的n次方 if ((n &(n - 1) )== 0 && n > 0)//要把n&(n-1)再

Leetcode 66 Plus One#include <vector>using namespace std;class Solution {public: vector<int> plusOne(vector<int>& digits) { int length = digits.size(); if (digits[length - 1] < 9

Leetcode 190 Reverse Bits#include <stdint.h>using namespace std;class Solution {public: uint32_t reverseBits(uint32_t n) { int result = 0; for (int i = 0; i < 32; i++) {

Leetcode 191 Number of 1 Bits#include <stdint.h>using namespace std;class Solution {public: int hammingWeight(uint32_t n) { //n减1是将n最右边的那个1变成0，如果这个1后面跟着0，则这些0全变成1，相与可以得到最右边的1 //1

Leetcode 204 Count Primes//比n小的质数有几个//（质数筛选定理）n不能够被小于等于根号n的任何质数整除，则n是一个质数#include <math.h>class Solution {public: int countPrimes(int n) { int count = 1; if (n <= 2)

Leetcode 326 Power of Threeusing namespace std;class Solution {public: bool isPowerOfThree(int n) { return n > 0 && 1162261467 % n == 0;//116226467是比int最大值小的最大的3的幂次，3的19次方 }};

Leetcode 338 Counting Bits#include <vector>#include <intrin.h>//__popcnt#include<nmmintrin.h>using namespace std;class Solution {public: vector<int> countBits(int num) { vector<int> bit

Leetcode 342 Power of Fourusing namespace std;class Solution {public: bool isPowerOfFour(int num) { if (num > 0 && 1073741824 % num == 0)//是2的幂次 if (num & 0x55555555)//2的幂次数中，4

Leetcode 461 Hamming Distanceclass Solution {public: int hammingDistance(int x, int y) { int z = x ^ y;//异或 int count = 0; while (z){ z = z &(z - 1);

Leetcode 477 Total Hamming Distance#include <vector>#include <intrin.h>//__popcnt#include<nmmintrin.h>using namespace std;class Solution {public: int hammingDistance(int x, int y) { int

Leetcode 628 Maximum Product of Three Numbers#include <vector>#include <algorithm>#include <windef.h>using namespace std;class Solution {public: int maximumProduct(vector<int>& nums) {

Leetcode 13 Roman to Integer//罗马数字采用七个罗马字母作数字//即Ⅰ（1）、X（10）、C（100）、M（1000）、V（5）、L（50）、D（500）#include <string>using namespace std;class Solution {public: int romanNumber(char c){ switch

LeetCode 20 Valid Parentheses#include <string>#include<stack>//使用c++中的栈using namespace std;class Solution {public: bool isValid(string s) { stack <char> stk;//声明一个字符栈 //遍历S中的全部字

LeetCode 21 Merge Two Sorted Lists#include <stddef.h>//否则NULL会报错为未定义的标识符using namespace std;struct ListNode { int val; ListNode *next; ListNode(int x) : val(x), next(NULL) {}};class Solu

LeetCode 27 Remove Element#include <vector>using namespace std;class Solution {public: int removeElement(vector<int>& nums, int val) { int size = nums.size(); int index = 0;

LeetCode 28 Implement strStr()#include <string>using namespace std;class Solution {public: int strStr(string haystack, string needle) { int position; if (haystack.find(needle) !=

LeetCode 35 Search Insert Position#include <vector>using namespace std;class Solution {public: int searchInsert(vector<int>& nums, int target) { if (nums[0] > target) return

Leetcode 88 Merge Sorted Array#include <vector>#include<algorithm>using namespace std;class Solution {public: void merge(vector<int>& nums1, int m, vector<int>& nums2, int n) { if (m ==

LeetCode 203 Remove Linked List Elements#include <stddef.h>//否则NULL会报错为未定义的标识符using namespace std; struct ListNode { int val; ListNode *next; ListNode(int x) : val(x), next(NULL) {} };

Leetcode 237 Delete Node in a Linked List#include <stddef.h>//否则NULL会报错为未定义的标识符using namespace std;struct ListNode { int val; ListNode *next; ListNode(int x) : val(x), next(NULL) {}};cla

LeetCode 283 Move Zeroes#include <vector>using namespace std;class Solution {public: void moveZeroes(vector<int>& nums) { int size = nums.size(); int index = 0; for (int i