제출 #233860

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
233860		LittleFlowers__	Network (BOI15_net)	C++17	0 / 100	6 ms	2688 KiB

net

#include <bits/stdc++.h>
using namespace std;
#define in ({int x=0;int c=getchar(),n=0;for(;!isdigit(c);c=getchar()) n=(c=='-');for(;isdigit(c);c=getchar()) x=x*10+c-'0';n?-x:x;})
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r){return l+rng()%(r-l+1);}
#define fasty ios_base::sync_with_stdio(0),cin.tie(0);
#define forinc(a,b,c) for(int a=b,_c=c;a<=_c;++a)
#define fordec(a,b,c) for(int a=b,_c=c;a>=_c;--a)
#define forv(a,b) for(auto&a:b)
#define fi first
#define se second
#define pb push_back
#define ii pair<int,int>
#define mt make_tuple
#define all(a) a.begin(),a.end()
#define reset(f, x) memset(f, x, sizeof(f))
#define bit(x,i) ((x>>(i-1))&1)
#define on(x,i) (x|(1ll<<(i-1)))
#define off(x,i) (x&~(1<<(i-1)))
#define gg exit(0);

const int N=100010;

int n;
vector<int> val;
vector<int> ad[N];

void dfs(int u,int p=-1){
    if(ad[u].size()<2) val.push_back(u);
    forv(v,ad[u]) if(v!=p)
        dfs(v,u);
}

main(){
    #define task "network"
    //freopen(task".inp","r",stdin);
    //freopen(task".out","w",stdout);

    n=in;
    forinc(i,2,n){
        int u=in,v=in;
        ad[u].pb(v);
        ad[v].pb(u);
    }

    int w=1; while(ad[w].size()<2) w++;

    dfs(w);

    cout<<(val.size()+1)/2<<"\n";
    for(int l=0,r=val.size()-1;l<r;l++,r--)
        cout<<val[l]<<" "<<val[r]<<"\n";
    if(val.size()&1) cout<<val[val.size()/2]<<" "<<val[0];
}

컴파일 시 표준 에러 (stderr) 메시지

net.cpp:34:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^

• Subtask 1: 0 / 18
• Subtask 2: 0 / 45
• Subtask 3: 0 / 37