思路: 对于每个数字A[i],使用单调栈找到A[i]作为最小值的所有区间数量,相乘并累加结果.时间复杂度O(n). 实现: class Solution { public: int sumSubarrayMins(vector<int>& A) { ; stack<int> st; int n = A.size(); ; ; i < n; i++) { while (!st.empty() && A[i] < A[st.top()]) { int…

Given an array of integers A, find the sum of min(B), where B ranges over every (contiguous) subarray of A. Since the answer may be large, return the answer modulo 10^9 + 7. Example 1: Input: [3,1,2,4] Output: 17 Explanation: Subarrays are [3], [1],…

Given an array of integers A, find the sum of min(B), where B ranges over every (contiguous) subarray of A. Since the answer may be large, return the answer modulo 10^9 + 7. Example 1: Input: [3,1,2,4] Output: 17 Explanation: Subarrays are [3], [1],…

Given an array of integers A, find the sum of min(B), where B ranges over every (contiguous) subarray of A. Since the answer may be large, return the answer modulo 10^9 + 7. Example 1: Input: [3,1,2,4] Output: 17 Explanation: Subarrays are [3], [1],…

2018-09-27 23:33:49 问题描述: 问题求解: 方法一.DP(MLE) 动态规划的想法应该是比较容易想到的解法了,因为非常的直观,但是本题的数据规模还是比较大的,如果直接使用动态规划,即使不MLE,也是肯定会在大规模的数据量上TLE的. public int sumSubarrayMins(int[] A) { int res = 0; int mod = (int)Math.pow(10, 9) + 7; int[][] dp = new int[A.length][A.len…

题目如下: 解题思路:我的想法对于数组中任意一个元素,找出其左右两边最近的小于自己的元素.例如[1,3,2,4,5,1],元素2左边比自己小的元素是1,那么大于自己的区间就是[3],右边的区间就是[4,5].那么对于元素2来说,和左边区间合并组成[2,3]以及和右边区间合并组成[2,4,5],这两段区间包括2在内的所有subarray的最小值都是2,其分别可以组成的subarry的个数是 len([3])和len([4,5]),左右区间合并在一起可以组成的subarray的个数是len([3])…

Given a circular array C of integers represented by A, find the maximum possible sum of a non-empty subarray of C. Here, a circular array means the end of the array connects to the beginning of the array.  (Formally, C[i] = A[i] when 0 <= i < A.leng…

2020-02-18 20:57:58 一.Maximum Subarray 经典的动态规划问题. 问题描述: 问题求解: public int maxSubArray(int[] nums) { int res = nums[0]; int n = nums.length; int[] dp = new int[n]; dp[0] = nums[0]; for (int i = 1; i < n; i++) { if (dp[i - 1] < 0) dp[i] = nums[i]; else…

Given a circular array C of integers represented by A, find the maximum possible sum of a non-empty subarray of C. Here, a circular array means the end of the array connects to the beginning of the array.  (Formally, C[i] = A[i]when 0 <= i < A.lengt…

Given a circular array C of integers represented by A, find the maximum possible sum of a non-empty subarray of C. Here, a circular array means the end of the array connects to the beginning of the array.  (Formally, C[i] = A[i] when 0 <= i < A.leng…