[zerojudge] d490 我也愛偶數

題目：https://zerojudge.tw/ShowProblem?problemid=d490
說明：數學題，用等差數列的總和公式來計算。

Java 版

import java.util.Scanner;

public class D490 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        while (in.hasNext()) {
            int a = in.nextInt();
            int b = in.nextInt();
            int c = 0;
            if(a == b){
                if(a % 2 == 0)
                    System.out.println(a);
                else
                    System.out.println("0");
            }
            else {
                int a1 = (a % 2 == 0) ? a : a+1;
                int an = (b % 2 == 0) ? b : b-1;
                int n = (an - a1) / 2 + 1;
                int sn = (a1 + an) * n / 2;
                System.out.println(sn);
            }
        }
    }
}

Python 版 (2022.08)

a, b = map(int, input().split(' '))
if a == b:
    if a % 2 == 0:
        print(a)
    else:
        print(0)
else:
    a1 = a if a % 2 == 0 else a + 1
    an = b if b % 2 == 0 else b - 1
    n = (an - a1) / 2 + 1
    sn = (a1 + an) * n / 2
    print(int(sn))