青蛙过河（前缀+二分）

 1 import java.util.*;
 2 
 3 public class Main {
 4     public static void main(String[] args) {
 5         Scanner scanner=new Scanner(System.in);
 6         int n=scanner.nextInt();
 7         long x=scanner.nextLong();
 8         //前缀和
 9         long[]arr=new long[n+1];
10         arr[0]=0;
11         for(int i=1;i<=n-1;i++) {
12             arr[i]=scanner.nextLong()+arr[i];
13         }
14         arr[n]=arr[n-1]+9999999999L;
15         int l=0;
16         int sum=0;
17         for(int i=1;i<=n;i++) {
18             if(arr[i]-arr[l]>=2L*x) {
19                 sum=Math.max(sum, i-l);
20                 l+=1;
21             }
22         }
23         System.out.print(sum);
24     }
25 }