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 Kotlin (1.0.0) (judge verdict: Time Limit Exceeded)


fun main(args: Array<String>) {
    val (K, S) = readLine()!!.split(" ").map { it.toInt() }

    val sum = calculateSumOfCombination(K, S)

    println(sum)
}

fun calculateSumOfCombination(K :Int, S: Int): Int {
    var sum = 0
    for (x in 0 .. K) {
        for (y in 0 .. K) {
            for (z in 0 .. K) {
                if (x + y + z == S) sum ++
            }
        }
    }
    return sum
}