Title linking
is still matter dp tree, then the root node as the bottom-up search can update
set \ (dp_ {i, 0} \) represents the i-th no, \ (dp_ {i,. 1} \) denotes the i th set a easily obtained state transition
\ (dp_ {i, 0} = \ sum {dp_ {j, 1}} son node (j is i,) \)
\ (dp_ {i,. 1} = 1 + \ sum {min (dp_ {j, 0}, dp_ {j, 1})} (j son node i) \)
#include<iostream>
#include<vector>
#include<algorithm>
#include<cstring>
#include<cstdio>
using namespace std;
const int maxn = 1507;
vector<int> son[maxn];
int in[maxn], dp[maxn][2];
void dfs(int fa) {
dp[fa][0] = 0;
dp[fa][1] = 1;
for(int i = 0; i < son[fa].size(); ++i) {
int v = son[fa][i];
dfs(v);
dp[fa][1] += min(dp[v][0], dp[v][1]);
dp[fa][0] += dp[v][1];
}
}
void run_case() {
int n;
while(cin >> n) {
memset(dp, 0, sizeof(dp)), memset(in, 0, sizeof(in));
for(int i = 0; i < n; ++i) {
int fa, num;
scanf("%d:(%d)", &fa, &num);
son[fa].clear();
for(int j = 0; j < num; ++j) {
int v;
scanf("%d", &v);
in[v]++;
son[fa].push_back(v);
}
}
for(int i = 0; i < n; ++i)
if(!in[i]) {
dfs(i);
cout << min(dp[i][0], dp[i][1]) << "\n";
break;
}
}
}
int main() {
//ios::sync_with_stdio(false), cout.tie(0);
cout.flags(ios::fixed);cout.precision(10);
run_case();
//cout.flush();
return 0;
}