Submission #554170

#	Time	Username	Problem	Language	Result	Execution time	Memory
554170		Alma	Traffic (IOI10_traffic)	C++17	0 / 100	0 ms	212 KiB

traffic

#include <bits/stdc++.h>
// #include "traffic.h"
using namespace std;
 
typedef long long int ll;
 
vector<vector<int>> graph;
vector<ll> cost;
vector<bool> visited;
vector<ll> DP;

int arenaCity;
 
ll traffic (int city) {
    if (DP[city] != -1) return DP[city];
 
    DP[city] = cost[city];
    visited[city] = true;
 
    for (int road: graph[city]) {
        if (!visited[road]) DP[city] += traffic(road);
    }
    return DP[city];
}

void untraffic (int city) {
    int bestCity = city;
    ll bestDiff = 1e9, maxCongestion = DP[city];

    for (int road: graph[city]) {
        if (DP[road] < maxCongestion) continue;
        ll diff = maxCongestion - DP[road];
        
        if (diff < bestDiff) {
            bestCity = road;
            bestDiff = diff;
        }
    }

    if (bestCity != city) {
        DP[city] -= DP[bestCity];
        DP[bestCity] = maxCongestion;
        arenaCity = bestCity;
    }
}

int LocateCentre(int N, int pp[], int S[], int D[]) {
    graph.assign(N, vector<int>());
    cost.clear();
    DP.assign(N, -1);
 
    for (int i = 0; i < N; i++) {
        graph[S[i]].push_back(D[i]);
        graph[D[i]].push_back(S[i]);
        cost.push_back(pp[i]);
    }
    visited.assign(N, false);
    ll congestion = traffic(0);
    arenaCity = 0;
    untraffic(0);    
    return arenaCity;
}

Compilation message (stderr)

traffic.cpp: In function 'int LocateCentre(int, int*, int*, int*)':
traffic.cpp:58:8: warning: unused variable 'congestion' [-Wunused-variable]
   58 |     ll congestion = traffic(0);
      |        ^~~~~~~~~~

• Subtask 1: 0 / 25
• Subtask 2: 0 / 25
• Subtask 3: 0 / 25
• Subtask 4: 0 / 25