前缀和(prefix sum/cumulative sum)的应用. 还用了一个知识点: a≡b(mod d) 则 a-b被d整除. 即:a与b对d同余,则a-b被d整除. class Solution(object): def subarraysDivByK(self, A, K): P = [0] for x in A: P.append((P[-1] + x) % K) count = collections.Counter(P) return sum(v*(v-1)/2 for v in…

作者: 负雪明烛 id: fuxuemingzhu 个人博客: http://fuxuemingzhu.cn/ 目录 题目描述 题目大意 解题方法 动态规划 前缀和求余 日期 题目地址:https://leetcode.com/problems/subarray-sums-divisible-by-k/ 题目描述 Given an array A of integers, return the number of (contiguous, non-empty) subarrays that ha…

题目如下: Given an array A of integers, return the number of (contiguous, non-empty) subarrays that have a sum divisible by K. Example 1: Input: A = [4,5,0,-2,-3,1], K = 5 Output: 7 Explanation: There are 7 subarrays with a sum divisible by K = 5: [4, 5,…

Given an array A of integers, return the number of (contiguous, non-empty) subarrays that have a sum divisible by K. Example 1: Input: A = [4,5,0,-2,-3,1], K = 5 Output: 7 Explanation: There are 7 subarrays with a sum divisible by K = 5: [4, 5, 0, -2…

Given an array A of integers, return the number of (contiguous, non-empty) subarrays that have a sum divisible by K. Example 1: Input: A = [4,5,0,-2,-3,1], K = 5 Output: 7 Explanation: There are 7 subarrays with a sum divisible by K = 5: [4, 5, 0, -2…

分析 这题场上前缀和都想出来了,然后就没有然后了...哭惹.jpg 前缀和相减能够得到任意一段连续区间的和,然后他们取余\(K\)看余数是否为0就能得到.这是朴素的遍历算法.那么反过来说,如果两个前缀和都对\(K\)余\(p\),那么他们相减一定能够被K整除. 我们就这么统计就可以了,然后一个简单的求和即可.想到不难,难的是想到. 代码 class Solution { public int subarraysDivByK(int[] A, int K) { int[] prefix = new…

Given an array A of integers, return the number of (contiguous, non-empty) subarrays that have a sum divisible by K. Example 1: Input: A = [4,5,0,-2,-3,1], K = 5 Output: 7 Explanation: There are 7 subarrays with a sum divisible by K = 5: [4, 5, 0, -2…

Given an array A of integers, return the number of (contiguous, non-empty) subarrays that have a sum divisible by K. Example 1: Input: A = [4,5,0,-2,-3,1], K = 5 Output: 7 Explanation: There are 7 subarrays with a sum divisible by K = 5: [4, 5, 0, -2…

Given an array A of integers, return the number of (contiguous, non-empty) subarrays that have a sum divisible by K. Example 1: Input: A = [4,5,0,-2,-3,1], K = 5 Output: 7 Explanation: There are 7 subarrays with a sum divisible by K = 5: [4, 5, 0, -2…

题目 Given an array of integers nums and an integer k, return the number of contiguous subarrays where the product of all the elements in the subarray is strictly less than k. Example 1: Input: nums = [10,5,2,6], k = 100 Output: 8 Explanation: The 8 su…