제출 #1033251

#제출 시각아이디문제언어결과실행 시간메모리
1033251aufanNetwork (BOI15_net)C++17
100 / 100
379 ms69676 KiB
#include <bits/stdc++.h> #define int long long #define fi first #define se second using namespace std; int32_t main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int n; cin >> n; vector<vector<int>> v(n + 1); for (int i = 0; i < n - 1; i++) { int a, b; cin >> a >> b; v[a].push_back(b); v[b].push_back(a); } vector<int> dp(n + 1); function<void(int, int)> dfs = [&](int x, int p) { if ((int)v[x].size() == 1) { dp[x] += 1; } for (auto z : v[x]) { if (z == p) continue; dfs(z, x); dp[x] += dp[z]; } }; int tot; for (int i = 1; i <= n; i++) { if ((int)v[i].size() > 1) { dfs(i, i); tot = dp[i]; break; } } int mn = n + 1, rt = -1; for (int i = 1; i <= n; i++) { if (dp[i] >= tot / 2) { if (dp[i] < mn) { mn = dp[i]; rt = i; } } } vector<int> leafs; function<void(int, int)> dfs2 = [&](int x, int p) { if ((int)v[x].size() == 1) { leafs.push_back(x); } for (auto z : v[x]) { if (z == p) continue; dfs2(z, x); } }; dfs2(rt, rt); if ((int)leafs.size() % 2 == 1) { leafs.push_back(leafs.back()); } cout << (int)leafs.size() / 2 << '\n'; for (int i = 0; i < (int)leafs.size() / 2; i++) cout << leafs[i] << " " << leafs[i + (int)leafs.size() / 2] << '\n'; return 0; }

컴파일 시 표준 에러 (stderr) 메시지

net.cpp: In function 'int32_t main()':
net.cpp:52:34: warning: 'tot' may be used uninitialized in this function [-Wmaybe-uninitialized]
   52 |                 if (dp[i] >= tot / 2) {
      |                              ~~~~^~~
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...