README_EN.md

923. 3Sum With Multiplicity

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Description

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.

Example 2:

Input: A = [1,1,2,2,2,2], target = 5

Output: 12

Explanation: 

A[i] = 1, A[j] = A[k] = 2 occurs 12 times:

We choose one 1 from [1,1] in 2 ways,

and two 2s from [2,2,2,2] in 6 ways.

 

Note:

<li><code>3 &lt;= A.length &lt;= 3000</code></li>

<li><code>0 &lt;= A[i] &lt;= 100</code></li>

<li><code>0 &lt;= target &lt;= 300</code></li>

Solutions

Python3

Java

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