# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
234557 | nishkarsh | Network (BOI15_net) | C++14 | 577 ms | 63072 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define pii pair<int,int>
#define pll pair<ll,ll>
#define pcc pair<char,char>
#define vi vector <int>
#define vl vector <ll>
#define sd(x) scanf("%d",&x)
#define slld(x) scanf("%lld",&x)
#define pd(x) printf("%d",x)
#define plld(x) printf("%lld",x)
#define pds(x) printf("%d ",x)
#define pllds(x) printf("%lld ",x)
#define pdn(x) printf("%d\n",x)
#define plldn(x) printf("%lld\n",x)
#define INF 2e9
#define INFLL 4e18
using namespace std;
ll powmod(ll base,ll exponent,ll mod){ // with mod < 1e9
ll ans=1;
while(exponent){
if(exponent&1)ans=(ans*base)%mod;
base=(base*base)%mod;
exponent/=2;
}
return ans;
}
ll gcd(ll a, ll b){
if(b==0) return a;
else return gcd(b,a%b);
}
const int upperlimit = 1e6+100;
const int mod = 1e9+7;
vi adj[upperlimit];
bool visited[upperlimit];
vi leaves;
void dfs(int node){
visited[node]=true;
int n=adj[node].size();
if(n==1) leaves.pb(node);
for(int i = 0; i < n; i++) if(! visited[adj[node][i]]) dfs(adj[node][i]);
}
int main() {
// freopen(".in","r",stdin);freopen(".out","w",stdout);
int n,a,b;
sd(n);
for(int i = 1; i < n; i++){
sd(a);sd(b);
adj[a].pb(b);adj[b].pb(a);
}
int m;
for(int i = 1; i <= n; i++){
m=adj[i].size();
if(m!=1){dfs(m);break;}
}
m=leaves.size();
int gg=m/2;
pdn(m-gg);
for(int i = 0; i+gg<m; i++){
pds(leaves[i]);pdn(leaves[i+gg]);
}
return 0;
}
Compilation message (stderr)
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