https://leetcode.com/problems/3sum-with-multiplicity/
Given an integer array A
, and an integer target
, return the number of tuples i, j, k
such that i < j < k
and A[i] + A[j] + A[k] == target
.
As the answer can be very large, return it modulo 10^9 + 7
.
Example 1:
Input: A = [1,1,2,2,3,3,4,4,5,5], target = 8 Output: 20 Explanation: Enumerating by the values (A[i], A[j], A[k]): (1, 2, 5) occurs 8 times; (1, 3, 4) occurs 8 times; (2, 2, 4) occurs 2 times; (2, 3, 3) occurs 2 times.