Problem:
Score : 200 points

Problem Statement

You are given two integers K and S.

Three variable X, Y and Z takes integer values satisfying 0≤X,Y,Z≤K.

How many different assignments of values to X, Y and Z are there such that X + Y + Z = S?

Constraints

2≤K≤2500

0≤S≤3K

K and S are integers.

Input

The input is given from Standard Input in the following format:

K S

Output

Print the number of the triples of X, Y and Z that satisfy the condition.

Sample Input 1

2 2

Sample Output 1

6

There are six triples of X, Y and Z that satisfy the condition:

X = 0, Y = 0, Z = 2

X = 0, Y = 2, Z = 0

X = 2, Y = 0, Z = 0

X = 0, Y = 1, Z = 1

X = 1, Y = 0, Z = 1

X = 1, Y = 1, Z = 0

Sample Input 2

5 15

Sample Output 2

1

The maximum value of X + Y + Z is 15, achieved by one triple of X, Y and Z.

Solution in JavaScript (node.js v5.12) (judge verdict: Time Limit Exceeded)

'use strict'

function main(input) {
  input = input
    .trim()
    .split(' ')
    .map(Number)
  const k = input[0]
  const s = input[1]
  let count = 0
  for (let xi = 0; xi <= k; xi++) {
    for (let yi = 0; yi <= k; yi++) {
      for (let zi = 0; zi <= k; zi++) {
        if (xi + yi + zi === s) count++
      }
    }
  }

  console.log(count)
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'))