Submission #376923

#	Time	Username	Problem	Language	Result	Execution time	Memory
376923		54skyxenon	Traffic (IOI10_traffic)	C++11	100 / 100	1167 ms	186476 KiB

traffic

#include <iostream>
#include <vector>
#include <numeric>
using namespace std;

#define ll long long

const int maxN = 1e6;

vector<int> adj[maxN];
int people[maxN];
int children[maxN];
int total;

void DFS(int P[], int src, int par) {
    ll ret = 0;

    for (int x : adj[src]) {
        if (x != par) {
            DFS(P, x, src);
            children[src] += children[x];
            people[src] = max(people[src], children[x]);
        }
    }

    people[src] = max(people[src], total - children[src] - P[src]);
    children[src] += P[src];
}

int LocateCentre(int N, int P[], int S[], int D[]) {
    ll minCongestion = 2e9;
    int ans = -1;

    total = accumulate(P, P + N, 0);

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

    DFS(P, 0, -1);

    for (int i = 0; i < N; i++) {
        ll congestionHere = people[i];

        if (congestionHere < minCongestion) {
            minCongestion = congestionHere;
            ans = i;
        }
    }

    return ans;
}

Compilation message (stderr)

traffic.cpp: In function 'void DFS(int*, int, int)':
traffic.cpp:16:8: warning: unused variable 'ret' [-Wunused-variable]
   16 |     ll ret = 0;
      |        ^~~

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