[POJ 1463] Strategic Game

[题目链接]

           http://poj.org/problem?id=1463

[算法]

       树形DP

[代码]

       

#include <algorithm>
#include <bitset>
#include <cctype>
#include <cerrno>
#include <clocale>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <limits>
#include <list>
#include <map>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <utility>
#include <vector>
#include <cwchar>
#include <cwctype>
#include <stack>
#include <limits.h>
using namespace std;
#define MAXN 1510

int i,n,tot,u,s,v;
int f[MAXN][2];
int head[MAXN];

struct Edge
{
        int to,nxt;
} e[MAXN << 1];
inline void addedge(int u,int v)
{
        tot++;
        e[tot] = (Edge){v,head[u]};
        head[u] = tot;    
}
inline void dp(int u,int fa)
{
        int i,v;
        f[u][0] = 0;
        f[u][1] = 1;
        for (i = head[u]; i; i = e[i].nxt)
        {
                v = e[i].to;
                if (v == fa) continue;
                dp(v,u);
                f[u][1] += min(f[v][0],f[v][1]);
                f[u][0] += f[v][1]; 
        }
}

int main() 
{
        
        while (scanf("%d",&n) != EOF)
        {
                tot = 0;
                for (i = 0; i < n; i++) head[i] = 0;
                for (i = 1; i <= n; i++)
                {
                        scanf("%d : (%d)",&u,&s);
                        while (s--)
                        {
                                scanf("%d",&v);
                                addedge(u,v);
                                addedge(v,u);        
                        }    
                }    
                dp(0,-1);
                printf("%d\n",min(f[0][0],f[0][1]));
        }
        
        return 0;
    
}