| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1306686 | jwpassion1 | 친구 (IOI14_friend) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
vector<int> graph[100000];
int trust[100000], pro[100000];
int dp[100000][2][2];
void dfs(int node) {
dp[node][1][0] = dp[node][1][1] = trust[node];
for (int i : graph[node]) {
dfs(i);
int tdp[2][2];
for (int i1 = 0; i1 < 2; i1++) for (int j1 = 0; j1 < 2; j1++) tdp[i1][j1] = dp[node][i1][j1] + dp[i][0][0];
int idp = max(max(dp[i][0][1], dp[i][1][0]), dp[i][1][1]);
if (!pro[i]) tdp[0][0] = max(tdp[0][0], dp[node][0][0] + idp);
else if (pro[i] == 1) {
tdp[0][1] = max(tdp[0][1], max(dp[node][0][0], dp[node][0][1]) + idp);
tdp[1][1] = max(tdp[1][1], max(dp[node][1][0], dp[node][1][1]) + idp);
}
else tdp[0][1] = max(tdp[0][1], dp[node][0][0] + idp);
for (int i1 = 0; i1 < 2; i1++) for (int j1 = 0; j1 < 2; j1++) dp[node][i1][j1] = tdp[i1][j1];
}
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
for (int i = 0; i < n; i++) cin >> trust[i];
for (int i = 1; i < n; i++) {
int par;
cin >> par >> pro[i];
graph[par].push_back(i);
}
for (int i = 0; i < n; i++) sort(graph[i].rbegin(), graph[i].rend());
dfs(0);
cout << max(max(dp[0][0][0], dp[0][0][1]), max(dp[0][1][0], dp[0][1][1])) << '\n';
}
