#include <bits/stdc++.h>
using namespace std;
template<class T, class U> bool chmax(T& a, const U& b){ if(a < b){ a = b; return 1; } return 0; }
int LocateCentre(int n, int p[], int s[], int d[]){
const int sum = reduce(p, p + n);
vector<vector<int>> g(n);
for(int i = 0; i < n - 1; i++){
const int a = s[i], b = d[i];
g[a].push_back(b);
g[b].push_back(a);
}
vector<int> siz(n, 1), dp(n);
auto dfs = [&](int from, int at, const auto& dfs) -> void {
for(int i : g[at]) if(i != from){
dfs(at, i, dfs);
chmax(dp[at], siz[i]);
siz[at] += siz[i];
}
chmax(dp[at], sum - siz[at]);
};
dfs(-1, 0, dfs);
return min_element(dp.begin(), dp.end()) - dp.begin();
}
Compilation message
traffic.cpp: In function 'int LocateCentre(int, int*, int*, int*)':
traffic.cpp:7:21: error: 'reduce' was not declared in this scope
const int sum = reduce(p, p + n);
^~~~~~
traffic.cpp:7:21: note: suggested alternative: 'rename'
const int sum = reduce(p, p + n);
^~~~~~
rename
