제출 #1250847

#제출 시각아이디문제언어결과실행 시간메모리
1250847tradzNetwork (BOI15_net)C++20
컴파일 에러
0 ms0 KiB
#include <bits/stdc++.h> #define TIME (1.0 * clock() / CLOCKS_PER_SEC) #define For(i,a,b) for(int i = a; i <= b; i++) #define Ford(i,a,b) for(int i = a; i >= b; i--) #define ll long long #define ii pair<int,int> #define fi first #define se second #define all(v) v.begin(),v.end() #define RRH(v) v.resize(unique(all(v)) - v.begin()) using namespace std; const int N = 1e6+7; const int M = 1e9+7; const ll oo = 3e18; mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()); long long GetRandom(long long l, long long r) { return uniform_int_distribution<long long> (l, r)(rng); } int n, cnt = 0; vector <int> g[N], ver[N]; int dp[N]; void dfs(int u, int rem, int pre = 0, int num) { dp[u] = 1; for (int v: g[u]) { if (v == pre) continue; if (rem == 1) { cnt++; dfs(v, 0, u, cnt); } else { dfs(v, 0, u, num); } dp[u] += dp[v]; } if (dp[u] == 1) ver[num].push_back(u); } int main() { ios::sync_with_stdio(0); cin.tie(0); #define TASK "" if (fopen (".inp", "r")) { freopen (".inp", "r", stdin); freopen (".out", "w", stdout); } if(fopen(TASK".inp", "r")) { freopen(TASK".inp", "r", stdin); freopen(TASK".out", "w", stdout); } cin >> n; for (int i = 1; i < n; i++) { int u, v; cin >> u >> v; g[u].push_back(v); g[v].push_back(u); } vector <pair <int, int>> ans; for (int i = 1; i <= n; i++) { if (g[i].size() >= 2) { dfs(i, 1); break; } } int i = 1; int j = cnt; while (i < j) { while (ver[i].size() && ver[j].size()) { ans.push_back({ver[i].back(), ver[j].back()}); ver[i].pop_back(); ver[j].pop_back(); } if (ver[i].size() == 0) i++; else j--; } if (i == j) { if (ver[i].size() != 0) { int l = 0; int r = ver[i].size() - 1; while (l < r) { ans.push_back({ver[i][l], ver[i][r]}); l++; r--; } if (l == r) { ans.push_back({ans[0].fi, ver[i][l]}); } } } cout << ans.size() << '\n'; for (int i = 0; i < ans.size(); i++) cout << ans[i].first << " " << ans[i].second << '\n'; cerr << "Time elapsed: " << TIME << " s.\n"; return 0; }

컴파일 시 표준 에러 (stderr) 메시지

net.cpp:26:43: error: default argument missing for parameter 4 of 'void dfs(int, int, int, int)'
   26 | void dfs(int u, int rem, int pre = 0, int num) {
      |                                       ~~~~^~~
net.cpp:26:30: note: ...following parameter 3 which has a default argument
   26 | void dfs(int u, int rem, int pre = 0, int num) {
      |                          ~~~~^~~~~~~
net.cpp: In function 'int main()':
net.cpp:47:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   47 |         freopen (".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~
net.cpp:48:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   48 |         freopen (".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
net.cpp:51:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   51 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
net.cpp:52:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   52 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~