Submission #414507

#	Time	Username	Problem	Language	Result	Execution time	Memory
414507		dxz05	Traffic (IOI10_traffic)	C++14	100 / 100	1110 ms	166764 KiB

traffic

#include "traffic.h"
#include <vector>

using namespace std;

const int MAXN = 1e6 + 3e2;

vector<int> g[MAXN];
int cnt[MAXN];

void dfs(int v, int p){
    for (int u : g[v]){
        if (u != p){
            dfs(u, v);
            cnt[v] += cnt[u];
        }
    }
}

int LocateCentre(int N, int pp[], int S[], int D[]) {
    for (int i = 0; i < N; i++) cnt[i] = pp[i];

    for (int i = 0; i < N - 1; i++){
        g[S[i]].push_back(D[i]);
        g[D[i]].push_back(S[i]);
    }

    dfs(0, 0);

    int mn = 2e9 + 5, ans = 0;
    for (int i = 0; i < N; i++){
        int cur = cnt[0] - cnt[i];
        for (int j : g[i]){
            if (cnt[j] < cnt[i]) cur = max(cur, cnt[j]);
        }
        if (cur < mn) mn = cur, ans = i;
    }

    return ans;
}

• Subtask 1: 25 / 25
• Subtask 2: 25 / 25
• Subtask 3: 25 / 25
• Subtask 4: 25 / 25