97k倍区间

⭐️难度：中等
🌟考点：暴力，2017省赛
📖

📚

import java.util.Scanner;

public class  Main {
    static int N = 100010;
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int k = sc.nextInt();
        int[] a = new int[N];

        for (int i = 1; i <= n; i++) {
            a[i] = sc.nextInt();
        }

        // 预处理
        long[] s = new long [N];
        for (int i = 1; i <= n; i++) {
            s[i] = s[i -1] + a[i];
        }

        long[] cnt = new long[N];
        long res = 0;
        for (int i = 1; i <= n; i++) {
            if(s[i] % k == 0){
                res ++;
            }
            res = res + cnt[(int)(s[i] % k)];
            cnt[(int)(s[i] % k)] ++;
        }
        System.out.println(res);
    }
}

🍎笔记