UVa 10817 (状压DP + 记忆化搜索) Headmaster's Headache

 1 #include <cstdio>
 2 #include <string>
 3 #include <iostream>
 4 #include <cstring>
 5 #include <sstream>
 6 using namespace std;
 7 
 8 const int maxs = 8;
 9 const int maxn = 125;
10 const int INF = 1000000000;
11 int s, m, n, c[maxn], st[maxn], d[maxn][1<<maxs][1<<maxs];
12 
13 int dp(int i, int s0, int s1, int s2)
14 {
15     if(i == m+n) return s2 == (1<<s)-1 ? 0 : INF;
16     int& ans = d[i][s1][s2];
17     if(ans >= 0) return ans;
18     ans = INF;
19     if(i >= m) ans = dp(i+1, s0, s1, s2);
20     int m0 = st[i]&s0, m1 = st[i]&s1;   //m0是该教师能教且现在没人教的科目，m1是能教且现在只有一个人教的集合
21     s0 ^= m0; s1 = (s1^m1)|m0; s2 |= m1;
22     ans = min(ans, c[i] + dp(i+1, s0, s1, s2));
23     return ans;
24 }
25 
26 int main()
27 {
28     //freopen("in.txt", "r", stdin);
29     int x;
30     string line;
31     while(getline(cin, line))
32     {
33         stringstream ss(line);
34         ss >> s >> m >> n;
35         if(s == 0) break;
36 
37         memset(st, 0, sizeof(st));
38         for(int i = 0; i < m+n; ++i)
39         {
40             getline(cin, line);
41             stringstream ss(line);
42             ss >> c[i];
43             while(ss >> x) st[i] |= (1 << (x-1));
44         }
45         memset(d, -1, sizeof(d));
46         printf("%d\n", dp(0, (1<<s)-1, 0, 0));
47     }
48 
49     return 0;
50 }