leetcode560.和为K的子数组 题目链接 算法 前缀和+哈希 时间复杂度O(n). 在解决这道题前需要先清楚,一个和为k的子数组即为一对前缀和的差值. 1.我们假设有这么一个子数组[i,j]满足数字和为k,那么就有pre[j] - pre[i-1] = k(注:pre数组为记录前缀和的数组),则pre[i-1] = pre[j] - k: 2.题目问找到nums数组中和为k的连续的子数组的数目,一开始想到是否会重叠,后来仔细看题目后发现题目中并没有限定子数组是否重叠,那么这道题只需要记录…

Given an array of integers and an integer k, you need to find the total number of continuous subarrays whose sum equals to k. Example 1: Input:nums = [1,1,1], k = 2 Output: 2  Note: The length of the array is in range [1, 20,000]. The range of number…

public class Solution { public int SubarraySum(int[] nums, int k) { , result = ; Dictionary<int, int> preSum = new Dictionary<int, int>(); preSum.Add(, ); ; i < nums.Length; i++) { sum += nums[i]; if (preSum.ContainsKey(sum - k)) { result +…

Description Given an array of integers and an integer k, you need to find the total number of continuous subarrays whose sum equals to k. Example 1: Input:nums = [1,1,1], k = 2 Output: 2 Note: The length of the array is in range [1, 20,000]. The rang…