过河问题 package ojtest; import java.util.Scanner; public class Sohu3 { public static int getmin(int[] arr){ if(arr.length==0) return 0; int jump=0,cur=0,next=0; for(int i=0;i<arr.length;i++){ if(cur<i){ jump++; if(cur==next) return -1; cur=next; } next=Math.max(next, i+arr[i]); } return cur>=arr.length?jump:(next>=arr.length?jump+1:-1); } public static void main(String[] args) { Scanner input=new Scanner(System.in); int n=input.nextInt(); int[] arr=new int[n]; for(int i=0;i<n;i++) arr[i]=input.nextInt(); System.out.println(getmin(arr)); } }