Submission #1390489

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define re(i,a,b) for(int i=(a);i<(b);i++)
#define repd(i,a,b) for(int i=(a);i>=(b);i--)
#define run(v) for(int k=head[v];k;k=e[k].ne)
#define v e[k].t
#define clr(a) memset(a,0,sizeof(a));
#define il inline
#define sz(a) ((int)a.size())
#define all(a) a.begin(),a.end()
#define mp make_pair
#define pb push_back 
#define w1 first
#define w2 second
#define adm(a,b,c) {a=a+b;if(a>=c)a-=c;else if(a<0)a+=c;}
typedef pair<int,int> pa;
typedef long long ll;typedef long double ld;typedef unsigned long long ull;
const int N=5e5+5,M=2e6+5,INF=1e9,mod=1e9+7;
const ll linf=1e18;const double eps=1e-8,pi=acos(-1);
il int gmin(int &a,int b){if(a>b)a=b;}il ll gmin(ll &a,ll b){if(a>b)a=b;}il int gmax(int &a,int b){if(a<b)a=b;}il ll gmax(ll &a,ll b){if(a<b)a=b;}
il void read(ll&x){ll f=1,t=0;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9'){t=t*10+ch-'0';ch=getchar();}x=t*f;}il ll read(ll&x,ll&y){read(x);read(y);}
il void read(int&x){int f=1,t=0;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}while(ch>='0'&&ch<='9'){t=t*10+ch-'0';ch=getchar();}x=t*f;}il int read(int&x,int&y){read(x);read(y);}
il void read(int&a,int&b,int&c){read(a);read(b);read(c);}il void read(ll&a,ll&b,ll&c){read(a);read(b);read(c);}
il int read(){int x;read(x);return x;}
il ll qpow(ll a,ll b,ll p){ll ret=1;for(;b;b>>=1,a=a*a%p)if(b&1)ret=ret*a%p;return ret;}il ll qpow(ll a,ll b){ll ret=1;for(;b;b>>=1,a=a*a%mod)if(b&1)ret=ret*a%mod;return ret;}
il ll qmul(ll a,ll b,ll p){ll ret=0;for(;b;b>>=1,a=(a<<1)%p)if(b&1)adm(ret,a,p);return ret;}il ll qmul(ll a,ll b){ll ret=0;for(;b;b>>=1,a=(a<<1)%mod)if(b&1)adm(ret,a,mod);return ret;}
il void judge(){
	freopen("data.in","r",stdin);
	freopen("data.out","w",stdout);}
il void gen(){freopen("data.in","w",stdout);}
int n,m,bin[30]={1};
int head[N],cnt,lg[N];
struct edge{int t,ne;}e[N];
void adde(int a,int b){e[++cnt]=(edge){b,head[a]};head[a]=cnt;}
#define pw(a) (1<<(a))
int gao(int x,int f){
	int S=0,K=0,P=0,res=0;
	run(x)if(v!=f){
		K=gao(v,x);
		S|=K&P;
		P|=K;
	}
	res=(P|(pw(lg[S]+1)-1))+1;
	return res;
}
int main(){
	read(n);
	re(i,1,n){int a,b;read(a,b);adde(a,b);adde(b,a);}
	lg[0]=-1;rep(i,1,1<<17)lg[i]=lg[i>>1]+1;
	cout<<lg[gao(1,0)];
}

Submission Info

Judge Result