242有效的字母异位词 349. 两个数组的交集 202快乐数

这几道都比较简单，主要是熟悉哈希的操作

class Solution {
public:bool isAnagram(string s, string t) {int alphab[26] = {0};for(int i=0; i < s.size(); i++){alphab[ s[i] - 'a' ]++;}for( int i=0; i<t.size(); i++){alphab[ t[i] - 'a' ]--;}for(int i=0; i<26; i++){if( alphab[i] !=0 )return false;}return true;}
};

class Solution {
public:vector<int> intersection(vector<int>& nums1, vector<int>& nums2) {unordered_set<int> set1;unordered_set<int> result1;for(int i=0 ;i < nums1.size(); i++){set1.insert(nums1[i]);}for(int i = 0; i<nums2.size(); i++){if( set1.find(nums2[i]) != set1.end() )result1.insert(nums2[i]);}return vector<int>(result1.begin(), result1.end() );}
};

class Solution {
public:int getsum(int n){int sum=0;while(n){sum += (n%10) * (n%10);n = n/10;}return sum;}bool isHappy(int n) {unordered_set<int> set1 {0};int result = 0;while(1){result = getsum(n);n = result;if( result == 1 )return true;if( set1.find(result) !=set1.end() )return false;elseset1.insert(result); }}
};