搜狐：袋鼠过河

袋鼠过河

dp用来保存跳了多少步

#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
#define FOR(I,N) for(int i=0;i<n;++i)
#define min(x,y) (x<y?x:y)
const int maxn = 1e4+5;
#define INF 1<<30
int arr[maxn];
int dp[maxn];
int main()
{
    int n,flag;
    while(cin>>n)
    {
        FOR(I,N) cin>>arr[i];
        for(int i=0;i<=n;++i)
        {
        	dp[i]=INF;
		}
        dp[0]=1;
        flag=1;
        FOR(I,N)
        {
            if(dp[i]==INF)
            {
                flag=0;
                break;
            }
            for(int j=i+1;j<=i+arr[i];++j)
            {
            	dp[j]=min(dp[i]+1,dp[j]);
                /*
                cout<<i<<endl; 
                FOR(I,N) 
				{
					cout<<dp[i]<<" ";
				} 
				cout<<endl;
				*/
            }
        }
        if(flag) cout<<dp[n]-1<<endl;
        else cout<<"-1"<<endl;
    }
    return 0;
}