제출 #119011

#제출 시각아이디문제언어결과실행 시간메모리
119011SOIVIEONENetwork (BOI15_net)C++14
0 / 100
19 ms12672 KiB
#include <bits/stdc++.h> //#include <ext/pb_ds/assoc_container.hpp> #define INF 1000000021 #define MOD 1000000007 #define pb push_back #define sqr(a) (a)*(a) #define M(a, b) make_pair(a,b) #define T(a, b, c) make_pair(a, make_pair(b, c)) #define F first #define S second #define all(x) (x.begin(), x.end()) #define deb(x) cerr << #x << " = " << x << '\n' #define N 522222 using namespace std; //using namespace __gnu_pbds; typedef long double ld; typedef long long ll; typedef pair<int,int> pii; typedef pair<ll, ll> pll; typedef vector<int> vi; typedef vector<ll> vll; //typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set; const ld pi = 2 * acos(0.0); template<class T> bool umin(T& a, T b){if(a>b){a=b;return 1;}return 0;} template<class T> bool umax(T& a, T b){if(a<b){a=b;return 1;}return 0;} template<class T, class TT> bool pal(T a, TT n){int k=0;for(int i=0;i<=n/2;i++){if(a[i]!=a[n-i-1]){k=1;break;}}return k?0:1;} //int month[] = {0,31,28,31,30,31,30,31,31,30,31,30,31}; int h[N], l[N]; vi v[N]; void dfs(int u, int e) { h[u] = h[e] + 1; for(auto it : v[u]) if(it != e) dfs(it, u); } bool kk(int x, int y) { return (h[x] < h[y]); } int main() { int n; cin >> n; for(int i = 2; i <= n; i ++) { int x, y; cin >> x >> y; v[x].pb(y); v[y].pb(x); } int mx = 0, root = 0; int cnt = 0; for(int i = 1; i <= n ;i ++) { if(mx < v[i].size()) { mx = v[i].size(); root = i; } if(v[i].size() == 1) l[++cnt] = i; } dfs(root, 0); // deb(root); sort(l + 1, l + cnt + 1, kk); vector<pii> ans; for(int i = 1; i <= cnt/2; i ++) { ans.pb(M(l[i], l[cnt-i+1])); } if(cnt & 1) ans.pb(M(l[cnt/2+1], l[1])); cout << ans.size() << '\n'; for(auto it : ans) cout << it.F << ' ' << it.S << '\n'; getchar(); getchar(); return 0; //ios::sync_with_stdio(false); //cin.tie(0); }

컴파일 시 표준 에러 (stderr) 메시지

net.cpp: In function 'int main()':
net.cpp:64:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(mx < v[i].size())
      ~~~^~~~~~~~~~~~~
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