Submission #1209904

#	Time	Username	Problem	Language	Result	Execution time	Memory
1209904		wazj2024	Traffic (IOI10_traffic)	C++20	Compilation error	0 ms	0 KiB

traffic

#include <bits/stdc++.h>
using namespace std;
static int N,P[1000000],S[1000000],D[1000000];
int peso[1000000];
long long cost[1000000];
vector<int> c[1000000];
int tp;
void dfs1(int u, int p, long long d, long long& total_cost) {
    peso[u] = P[u];
    total_cost += (long long)P[u] * d;
    for (int v : c[u]) {
        if (v != p) {
            dfs1(v, u, d + 1, total_cost);
            peso[u] += peso[v];
        }
    }
}
void dfs2(int u, int p) {
    for (int v : c[u]) {
        if (v != p) {
            cost[v] = cost[u] + (long long)(tp - 2 * tp[v]);
            dfs2(v, u);
        }
    }
}
int LocateCentre(int N, int P[], int S[], int D[]) {
    ::N = N;
    tp = 0;
    for (int i = 0; i < N; ++i) {
        c[i].clear();
        tp += P[i];
    }
    for (int i = 0; i < N - 1; ++i) {
        c[S[i]].push_back(D[i]);
        c[D[i]].push_back(S[i]);
    }
    long long total_cost = 0;
    dfs1(0, -1, 0, total_cost);
    cost[0] = total_cost;
    dfs2(0, -1);
    int best = 0;
    for (int i = 1; i < N; ++i) {
        if (cost[i] < cost[best]) best = i;
    }
    return best;
}
int main(){
   int i;
   scanf("%d",&N);
   for (i=0;i<N;i++) scanf("%d",&P[i]);
   for (i=0;i<N-1;i++) scanf("%d%d",&S[i],&D[i]);
   int r = LocateCentre(N,P,S,D);
   printf("%d\n",r);
   return 0;
}

Compilation message (stderr)

traffic.cpp: In function 'void dfs2(int, int)':
traffic.cpp:21:56: error: invalid types 'int[int]' for array subscript
   21 |             cost[v] = cost[u] + (long long)(tp - 2 * tp[v]);
      |                                                        ^
traffic.cpp: In function 'int main()':
traffic.cpp:49:9: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |    scanf("%d",&N);
      |    ~~~~~^~~~~~~~~
traffic.cpp:50:27: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   50 |    for (i=0;i<N;i++) scanf("%d",&P[i]);
      |                      ~~~~~^~~~~~~~~~~~
traffic.cpp:51:29: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |    for (i=0;i<N-1;i++) scanf("%d%d",&S[i],&D[i]);
      |                        ~~~~~^~~~~~~~~~~~~~~~~~~~