Submission #919879

#	Time	Username	Problem	Language	Result	Execution time	Memory
919879		boris_mihov	Traffic (IOI10_traffic)	C++17	100 / 100	945 ms	159364 KiB

traffic

#include "traffic.h"
#include <algorithm>
#include <iostream>
#include <numeric>
#include <cassert>
#include <vector>

typedef long long llong;
const int MAXN = 1e6 + 10;
const int INF  = 1e9;

int n;
int p[MAXN];
llong sz[MAXN], sum;
std::vector <int> g[MAXN];

void dfs(int node, int par)
{
    sz[node] = p[node];
    for (const int &u : g[node])
    {
        if (u == par)
        {
            continue;
        }

        dfs(u, node);
        sz[node] += sz[u];
    }
}

int find(int node, int par)
{
    for (const int &u : g[node])
    {
        if (u == par)
        {
            continue;
        }

        if (sz[u] > sum / 2)
        {
            return find(u, node);
        }
    }

    return node;
}

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

    for (int i = 0 ; i < n ; ++i)
    {
        p[i] = pp[i];
        sum += pp[i];
    }

    dfs(0, -1);
    return find(0, -1);
}

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