#include<bits/stdc++.h> using namespace std; #define fi first #define se second #define pb push_back #define eb emplace_back #define vi vector<int> #define pi pair<int,int> #define sz(v) (int)(v).size() #define all(v) (v).begin(), (v).end() #define compact(v) (v).erase(unique(all(v)), (v).end()) template<class T> using upq = priority_queue<T, vector<T>, greater<T>>; template<class T> int lwrbound(const vector<T>& a, const T& b, const int s = 0){return int(lower_bound(s + all(a), b) - a.begin());} template<class T> int uprbound(const vector<T>& a, const T& b, const int s = 0){return int(upper_bound(s + all(a), b) - a.begin());} #define FOR(i, a, b) for(int i = (a); i <= (b); i++) #define ROF(i, a, b) for(int i = (a); i >= (b); i--) #define sumof(x) accumulate(all(x), 0ll) #define dbg(x) "[" << #x " = " << (x) << "]" #define el "\n" using ll = long long; using ld = long double; template<class T> bool ckmx(T& a, const T b){return (a < b ? a = b, true : false);} template<class T> bool ckmn(T& a, const T b){return (a > b ? a = b, true : false);} const ll INF = 1e15; void Main() { int N; cin >> N; vector<ll> nxt(N + 1), w(N + 1); FOR(i, 1, N){ cin >> nxt[i] >> w[i]; } vi vis(N + 1), cycle(N + 1); FOR(i, 1, N) if(!vis[i]){ int x = i; for(; !vis[x]; x = nxt[x]){ vis[x] = i; } if(vis[x] == i){ cycle[x] = 1; int sz = 1; for(int v = nxt[x]; v != x; v = nxt[v]){ cycle[v] = 1, ++sz; } if(sz == N){ cout << "0\n"; return; } } } vector<ll> Mx(N + 1), MxNC(N + 1); FOR(i, 1, N){ ckmx(Mx[nxt[i]], w[i]); if(!cycle[i]){ ckmx(MxNC[nxt[i]], w[i]); } } ll ans = sumof(Mx); FOR(i, 1, N) if(cycle[i]){ ll upd = -INF; for(int x = nxt[i]; x != i; x = nxt[x]){ ckmx(upd, -Mx[x] + MxNC[x]); cycle[x] = 0; } ckmx(upd, -Mx[i] + MxNC[i]); ans += upd; } cout << sumof(w) - ans << el; } int32_t main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); #define name "InvMOD" if(fopen(name".INP", "r")){ freopen(name".INP", "r", stdin); freopen(name".OUT", "w", stdout); } int t = 1; while(t--) Main(); return 0; }

telegraph.cpp: In function 'int32_t main()':
telegraph.cpp:92:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |         freopen(name".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
telegraph.cpp:93:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |         freopen(name".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~