青蛙过河（前缀+二分）

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner=new Scanner(System.in);
        int n=scanner.nextInt();
        long x=scanner.nextLong();
        //前缀和
        long[]arr=new long[n+1];
        arr[0]=0;
        for(int i=1;i<=n-1;i++) {
            arr[i]=scanner.nextLong()+arr[i];
        }
        arr[n]=arr[n-1]+9999999999L;
        int l=0;
        int sum=0;
        for(int i=1;i<=n;i++) {
            if(arr[i]-arr[l]>=2L*x) {
                sum=Math.max(sum, i-l);
                l+=1;
            }
        }
        System.out.print(sum);
    }
}