HDU 4778 Gems Fight!(DP)

题目链接

当我放弃的时候过了。sb啊，卡常数！！！

换了好几个姿势，本来没写预处理，预处理+俩剪枝，尼玛就过了。。

  1 #include <stdio.h>

  2 #include <string.h>

  3 #include <iostream>

  4 #include <queue>

  5 using namespace std;

  6 #define INF 0x3f3f3f3f

  7 #define LL __int64

  8 int bag[31][31];

  9 int sum[31];

 10 int dp[1<<21];

 11 int bg[1<<21][11];

 12 int g,b,s;

 13 int temp[31];

 14 int dfs(int x)

 15 {

 16     int maxz = 0,i,j,flag,st;

 17     if(dp[x] != -1)

 18     return dp[x];

 19     for(i = 0;i < b;i ++)

 20     {

 21         if((x&(1<<i)) == 0)

 22         {

 23             flag = 0;

 24             st = 0;

 25             for(j = 0;j < g;j ++)

 26             {

 27                 flag += bg[x|(1<<i)][j]/s - bg[x][j]/s;

 28                 st += sum[j]/s - bg[x|(1<<i)][j]/s;

 29             }

 30             if(flag)

 31             {

 32                 if(maxz >= st + flag) continue;//剪枝就是这两个剪枝

 33                 if(maxz < dfs(x|(1<<i))+flag)

 34                 maxz = dfs(x|(1<<i))+flag;

 35             }

 36             else

 37             {

 38                 if(maxz >= st) continue;//剪枝

 39                 if(maxz < st - dfs(x|(1<<i)))

 40                 maxz = st - dfs(x|(1<<i));

 41             }

 42         }

 43     }

 44     return dp[x] = maxz;

 45 }

 46 int main()

 47 {

 48     int i,j,k,n,num,sp,sa,sb;

 49     while(scanf("%d%d%d",&g,&b,&s)!=EOF)

 50     {

 51         if(g == 0&&b == 0&&s == 0)

 52         break;

 53         for(i = 0;i < (1<<b);i ++)

 54         {

 55             dp[i] = -1;

 56             for(j = 0;j < g;j ++)

 57             bg[i][j] = 0;

 58         }

 59         for(i = 0;i < b;i ++)

 60         {

 61             for(j = 0;j < g;j ++)

 62             {

 63                 bag[i][j] = 0;

 64             }

 65         }

 66         for(j = 0;j < g;j ++)

 67         {

 68             sum[j] = temp[j] = 0;

 69         }

 70         for(i = 0;i < b;i ++)

 71         {

 72             scanf("%d",&n);

 73             for(j = 1;j <= n;j ++)

 74             {

 75                 scanf("%d",&num);

 76                 bag[i][num-1]++;

 77                 sum[num-1] ++;

 78             }

 79         }

 80         for(i = 0;i < (1<<b);i ++)//扯淡的预处理

 81         {

 82             for(j = 0;j < b;j ++)

 83             {

 84                 if(i&(1<<j))

 85                 {

 86                     for(k = 0;k < g;k ++)

 87                     bg[i][k] += bag[j][k];

 88                 }

 89             }

 90         }

 91         sp = 0;

 92         for(i = 0;i < g;i ++)

 93         {

 94             sp += sum[i]/s;

 95         }

 96         sa = dfs(0);

 97         sb = sp - sa;

 98         printf("%d\n",sa-sb);

 99     }

100     return 0;

101 }