#include <bits/stdc++.h> // see /general/running-code-locally using namespace std; using ll = long long; using vi = vector<int>; #define pb push_back #define all(x) begin(x), end(x) #define sz(x) (int)(x).size() using pi = pair<int,int>; #define f first #define s second #define mp make_pair void setIO(string name = "") { cin.tie(0)->sync_with_stdio(0); // see /general/fast-io if (sz(name)) { freopen((name+".in").c_str(), "r", stdin); // see /general/io freopen((name+".out").c_str(), "w", stdout); } } const int SZ = 1000000; int n, p[SZ]; vector<int> adjlist[SZ]; int pref[SZ+1]; int ans[SZ]; void dfs(int node, int prev) { ans[node] = 0; for(int v: adjlist[node]) { if(v==prev) { ans[node] = max(ans[node], pref[0] - pref[node]); continue; } ans[node] = max(ans[node], pref[v]); dfs(v, node); } } int fill_pre(int node, int prev) { pref[node] = p[node]; for(int v: adjlist[node]) { if(v==prev) { continue; } fill_pre(v, node); pref[node] += pref[v]; } return pref[node]; } int LocateCentre(int nc, int pc[], int sc[], int dc[] ) { n = nc; for(int i=0; i<n; i++) { p[i] = pc[i]; } for(int i=0; i<n-1; i++) { adjlist[sc[i]].push_back(dc[i]); adjlist[dc[i]].push_back(sc[i]); } fill_pre(0, -1); dfs(0, -1); int sol; int min_cong = 2000000001; for(int i=0; i<n; i++) { if(min_cong>ans[i]) { min_cong = ans[i]; sol = i; } } return sol; }

traffic.cpp: In function 'void setIO(std::string)':
traffic.cpp:19:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |   freopen((name+".in").c_str(), "r", stdin); // see /general/io
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp:20:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |   freopen((name+".out").c_str(), "w", stdout);
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp: In function 'int LocateCentre(int, int*, int*, int*)':
traffic.cpp:81:12: warning: 'sol' may be used uninitialized in this function [-Wmaybe-uninitialized]
   81 |     return sol;
      |            ^~~