HDU 4649 Professor Tian(DP)

题目链接

暴力水过的，比赛的时候T了两次，优化一下初始化，终于水过了。

 #include <cstdio>
 #include <cstring>
 #include <string>
 #include <algorithm>
 using namespace std;
 #define MOD 1000000007
 #define LL __int64
 double dp[][<<];
 int que[<<];
 int flag[<<];
 double o[];
 char str[];
 int p[];
 int judge(char s)
 {
     if(s == '^')
     return ;
     else if(s == '&')
     return ;
     else if(s == '|')
     return ;
     return ;
 }
 int main()
 {
     int n,cas = ,i,j,x,t1,t2,num,tnum;
     while(scanf("%d",&n)!=EOF)
     {
         scanf("%d",&x);
         for(i = ;i <= n;i ++)
         scanf("%d%*c",&p[i]);
         for(i = ;i <= n;i ++)
         scanf("%c%*c",&str[i]);
         for(i = ;i <= n;i ++)
         scanf("%lf",&o[i]);
         flag[x] = ;
         num = ;
         que[] = x;
         dp[][x] = 1.0;
         t1 = ;t2 = ;
         for(i = ;i <= n;i ++)
         {
             tnum = num;
             for(j = ;j <= num;j ++)
             {
                 dp[t2][que[j]] += dp[t1][que[j]]*o[i];
                 int temp,z = judge(str[i]);
                 if( z == )
                 {
                     temp = que[j]^p[i];
                     if(!flag[temp])
                     {
                         flag[temp] = ;
                         que[++tnum] = temp;
                     }
                     dp[t2][temp] += dp[t1][que[j]]*(1.0-o[i]);
                 }
                 else  if(z == )
                 {
                     temp = que[j]&p[i];
                     if(!flag[temp])
                     {
                         flag[temp] = ;
                         que[++tnum] = temp;
                     }
                     dp[t2][temp] += dp[t1][que[j]]*(1.0-o[i]);
                 }
                 else
                 {
                     temp = que[j]|p[i];
                     if(!flag[temp])
                     {
                         flag[temp] = ;
                         que[++tnum] = temp;
                     }
                     dp[t2][temp] += dp[t1][que[j]]*(1.0-o[i]);
                 }
             }
             num = tnum;
             swap(t2,t1);
             for(j = ;j <= num;j ++)
             dp[t2][que[j]] = 0.0;
         }
         double ans = ;
         for(i = ;i <= num;i ++)
         {
             ans += que[i]*dp[t1][que[i]];
             flag[que[i]] = ;
             dp[t1][que[i]] = 0.0;
         }
         printf("Case %d:\n%.6f\n",cas++,ans);
     }
     return ;
 }