이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
#include<bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define pb push_back
typedef pair<int, int> ii;
const int N = 5e5 + 10;
const int oo = 1e9;
int n;
int deg[N], sz[N];
bool visit[N];
vector<int> lef, rig, vi[N];
void dfs(int pre, int u) {
sz[u] = 1;
for(int v: vi[u]) if(v != pre)
dfs(u, v), sz[u] += sz[v];
// :D
}
void findcen(int pre, int u, int sz1, bool spm) {
if(spm) visit[u] = true;
if(!spm) {
for(int v: vi[u]) if(v != pre && sz[v] * 2 >= sz1) {
findcen(u, v, sz1, 0);
return;
}
}
visit[u] = true;
for(int v: vi[u]) if(v != pre) findcen(u, v, sz1, 1);
}
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n;
for(int i = 1; i < n; ++i) {
int u, v; cin >> u >> v;
vi[u].pb(v); vi[v].pb(u);
deg[u] ++; deg[v] ++;
}
dfs(1, 1);
findcen(1, 1, sz[1], 0);
for(int i = 1; i <= n; ++i) if(deg[i] ==1) {
if(!visit[i]) lef.pb(i);
else rig.pb(i);
}
vector<ii> ans;
int ptr1 = 0, ptr2 = 0;
while(ptr1 < lef.size() && ptr2 < rig.size()) {
ans.pb(ii(lef[ptr1], rig[ptr2]));
ptr1 ++; ptr2 ++;
}
while(ptr1 < lef.size() - 1) ans.pb(ii(lef[ptr1], lef[ptr1 + 1])), ptr1 += 2;
if(ptr1 < lef.size()) ans.pb(ii(lef[ptr1], rig[0]));
while(ptr2 < rig.size() - 1) ans.pb(ii(rig[ptr2], rig[ptr2 + 1])), ptr2 += 2;
if(ptr2 < rig.size()) ans.pb(ii(rig[ptr2], lef[0]));
cout << ans.size() << '\n';
for(ii v: ans) cout << v.fi << ' ' << v.se << '\n';
}
컴파일 시 표준 에러 (stderr) 메시지
net.cpp: In function 'int main()':
net.cpp:55:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while(ptr1 < lef.size() && ptr2 < rig.size()) {
~~~~~^~~~~~~~~~~~
net.cpp:55:37: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while(ptr1 < lef.size() && ptr2 < rig.size()) {
~~~~~^~~~~~~~~~~~
net.cpp:59:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while(ptr1 < lef.size() - 1) ans.pb(ii(lef[ptr1], lef[ptr1 + 1])), ptr1 += 2;
~~~~~^~~~~~~~~~~~~~~~
net.cpp:60:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(ptr1 < lef.size()) ans.pb(ii(lef[ptr1], rig[0]));
~~~~~^~~~~~~~~~~~
net.cpp:61:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
while(ptr2 < rig.size() - 1) ans.pb(ii(rig[ptr2], rig[ptr2 + 1])), ptr2 += 2;
~~~~~^~~~~~~~~~~~~~~~
net.cpp:62:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if(ptr2 < rig.size()) ans.pb(ii(rig[ptr2], lef[0]));
~~~~~^~~~~~~~~~~~
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |
# | Verdict | Execution time | Memory | Grader output |
---|
Fetching results... |