P2016 战略游戏(树形dp)

P2016 战略游戏

#include <iostream>
#include <cstdio>
#include <string>
#include <algorithm>
#include <vector>
#include <queue>
#include <stack>
#include <cstring>
#include <set>
#include <unordered_map>
#include <cmath>
#include <map>
#include <cctype>
#include <cstdlib>
#include <deque>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
const int MN = 65005;
const int MAXN = 1000010;
const int INF = 0x3f3f3f3f;
#define IOS ios::sync_with_stdio(false)
#define lowbit(x) ((x)&(-x))

int f[2000][2];
int head[MAXN];
int nxt[MAXN];
int ver[MAXN];
int cnt;
inline void add(int x, int y) {
	ver[++cnt] = y;
	nxt[cnt] = head[x];
	head[x] = cnt;
}

void dp(int p, int fa) {
	f[p][1] = 1;
	for (int i = head[p]; i; i = nxt[i]) {
		int v = ver[i];
		if (v == fa)
			continue;
		dp(v, p);
		f[p][0] += f[v][1];
		f[p][1] += min(f[v][1], f[v][0]);
	}
}

int main() {
	int n;
	scanf("%d", &n);
	int x, y, t;
	for (int i = 1; i <= n; i++) {
		scanf("%d %d", &x, &t);
		for (int j = 1; j <= t; j++) {
			scanf("%d", &y);
			add(x + 1, y + 1);
			add(y + 1, x + 1);
		}
	}
	dp(1, 0);
	printf("%d", min(f[1][0], f[1][1]));
	return 0;
}