HDU 4405 aeroplane chess

Question:

Hzz starts at 0, and then hzz throws the dice. If the dice is I, it goes forward to step I. When the position of hzz is greater than or equal to N, it ends and calculates the expected number of dice.

With M direct points (x, y), you can directly go to Y

Expect to push from the back

When I is not equal to any x

DP [I] = seg (1/6 * DP [I + k]) + 1

Otherwise

DP [I] = DP [y]

 1 #include<iostream> 2 #include<string> 3 #include<cstdio> 4 #include<vector> 5 #include<queue> 6 #include<stack> 7 #include<algorithm> 8 #include<cstring> 9 #include<stdlib.h>10 using namespace std;11 #define pb push_back12 struct node{13     int x,y;14 }p[1010];15 int cmp(node a,node b){16     return a.x<b.x;17 }18 int main()19 {20     int n,m;21     while(cin>>n>>m,n+m){22         double dp[101010];23         memset(dp,0,sizeof(dp));24         for(int i=0;i<m;i++)25             scanf("%d%d",&p[i].x,&p[i].y);26         sort(p,p+m,cmp);27         int cnt=m-1;28         for(int i=n-1;i>=0;i--){29               dp[i]=1;30               if(cnt>=0&&i==p[cnt].x){31                dp[i]=dp[p[cnt].y];32                cnt--;33                continue;34               }35               for(int j=6;j>=1;j--)36                 dp[i]+=1.0/6*dp[i+j];37         }38         printf("%.4f\n",dp[0]);39     }40 }