- Difficulty: Medium
- Tags: LeetCode, Medium, Array, Two Pointers, Binary Search, Prefix Sum, leetcode-1712, O(n)
Problem
A split of an integer array is good if:
- The array is split into three non-empty contiguous subarrays - named
left
,mid
,right
respectively from left to right. - The sum of the elements in
left
is less than or equal to the sum of the elements inmid
, and the sum of the elements inmid
is less than or equal to the sum of the elements inright
.
Given nums
, an array of non-negative integers, return the number of good ways to split nums
. As the number may be too large, return it modulo 109 + 7
.
Example 1:
Input: nums = [1,1,1] Output: 1 Explanation: The only good way to split nums is [1] [1] [1].
Example 2:
Input: nums = [1,2,2,2,5,0] Output: 3 Explanation: There are three good ways of splitting nums: [1] [2] [2,2,5,0] [1] [2,2] [2,5,0] [1,2] [2,2] [5,0]
Example 3:
Input: nums = [3,2,1] Output: 0 Explanation: There is no good way to split nums.
Constraints:
3 <= nums.length <= 105
0 <= nums[i] <= 104