Submission #1037368

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037368		onbert	Friend (IOI14_friend)	C++17	100 / 100	25 ms	7772 KiB

friend

#include "friend.h"
#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
int n, a[maxn], t[maxn];
vector<int> adj[maxn];

int dp[maxn][2];
void dfs(int u) {
    for (int v:adj[u]) dfs(v);
    dp[u][0] = 0;
    for (int v:adj[u]) {
        if (t[v]==0) dp[u][0] += dp[v][1];
        if (t[v]==1) dp[u][0] += dp[v][0];
        if (t[v]==2) dp[u][0] += dp[v][0];
    }
    int def = dp[u][0];
    int val = def, cur = 0, mx = 0;
    for (int v:adj[u]) {
        if (t[v]==0) def += dp[v][0] - dp[v][1];
        else if (t[v]==1) cur += dp[v][1] - dp[v][0];
        else if (t[v]==2) mx = max(dp[v][1] - dp[v][0] + cur, mx);
        val = max(def + max(cur, mx), val);
    }
    
    dp[u][1] = a[u];
    for (int v:adj[u]) {
        if (t[v]==0) dp[u][1] += dp[v][0];
        if (t[v]==1) dp[u][1] += dp[v][1];
        if (t[v]==2) dp[u][1] += dp[v][0];
    }
    dp[u][1] = max({val, dp[u][0], dp[u][1]});
}

int findSample(int N, int confidence[], int host[], int T[]){
	n = N;
    for (int i=0;i<n;i++) a[i] = confidence[i];
    t[0] = T[0];
    for (int i=1;i<n;i++) t[i] = T[i];
    for (int i=1;i<n;i++) adj[host[i]].push_back(i);
    dfs(0);
    // for (int j=0;j<=1;j++) {
    //     cout << j << endl;
    //     for (int i=0;i<n;i++) cout << dp[i][j] << " "; cout << endl;
    // }
    return dp[0][1];
}

• Subtask 1: 11 / 11
• Subtask 2: 8 / 8
• Subtask 3: 8 / 8
• Subtask 4: 19 / 19
• Subtask 5: 23 / 23
• Subtask 6: 31 / 31