其实也可以求前i项和，再挨着做差，把二次复杂度降为一次

其实也可以求前i项和，再挨着做差，把二次复杂度降为一次：

import java.util.*;
public class Main{
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()){
            int n = sc.nextInt();
            int t = sc.nextInt();
            int c = sc.nextInt();
            int[] v = new int[n];
            for(int i = 0; i < n; ++i) v[i] = sc.nextInt();
            int r = 0;
            for(int i = 0; i <= n - c; ++i){
                int sum = 0;
                for(int j = i; j < i + c; ++j){
                    sum += v[j];
                }
                if(sum <= t) r++;
            }
            System.out.println(r);
        }
    }
}