1、题目

https://leetcode-cn.com/problems/subarray-sum-equals-k/solution/dai-ni-da-tong-qian-zhui-he-cong-zui-ben-fang-fa-y/

2、题意

题解1：前缀和+哈希表

class Solution {
public:int subarraySum(vector<int>& nums, int k) {unordered_map<int,int> m;m[0] = 1;int res = 0,sum = 0;for(auto&x:nums){sum+=x;res+=m[sum-k];m[sum]++;}return res;}
};