Submission #503194

#	Time	Username	Problem	Language	Result	Execution time	Memory
503194		Hacv16	Traffic (IOI10_traffic)	C++17	50 / 100	402 ms	152736 KiB

traffic

#include<bits/stdc++.h>
#include "traffic.h"
using namespace std;

typedef long long ll;
typedef pair<int, int> pii;

const int MAX = 1e6 + 15;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;

#define pb push_back
#define sz(x) (int) x.size()
#define fr first
#define sc second
#define mp make_pair
#define all(x) x.begin(), x.end()

int fans = 0;
vector<int> adj[MAX], child(MAX), cong(MAX), fan(MAX); 
//child keeps number of children, cong worst congestion, fan number of fans in ith city

void dfs(int x, int p){
    for(auto v : adj[x]){
        if(v == p) continue;

        dfs(v, x);

        child[x] += child[v];
        cong[x] = max(cong[x], child[v]); //maximum congestion
    }

    cong[x] = max(cong[x], fans - cong[x] - fan[x]); //worst between children and others (that come through parent)
    child[x] += fan[x]; //add to children for next node processing
}

int LocateCentre(int n, int p[], int s[], int d[]){
    for(int i = 0; i < n; i++){
        fans += p[i];
        fan[i] = p[i];
    }

    for(int i = 0; i < n - 1; i++){
        adj[s[i]].pb(d[i]);
        adj[d[i]].pb(s[i]);
    }

    dfs(0, -1);

    int id, sm = INF;

    for(int i = 0; i < n; i++){ //want city with best worst congestion
        if(sm > cong[i]){
            id = i, sm = cong[i];
        }
    }

    return id;
}

/*int main(){
    setIO();

    int P[] = {10, 10, 10, 20, 20};
    int S[] = {0, 1, 3, 4};
    int D[] = {2, 2, 2, 3};

    cout << LocateCentre(5, P, S, D) << '\n';

    return 0;
}*/

Compilation message (stderr)

traffic.cpp: In function 'int LocateCentre(int, int*, int*, int*)':
traffic.cpp:58:12: warning: 'id' may be used uninitialized in this function [-Wmaybe-uninitialized]
   58 |     return id;
      |            ^~

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