Submission #973259

#	Time	Username	Problem	Language	Result	Execution time	Memory
973259		vjudge1	Easter Eggs (info1cup17_eastereggs)	C++17	100 / 100	12 ms	740 KiB

eastereggs

#include <vector>
#include <utility>
#include "grader.h"

#define MAX_N 513
#define MAX_M (2*MAX_N)
int head[MAX_N], vv[MAX_M], nxt[MAX_M], eo,timer,tin[MAX_N],aux[MAX_N];
void link(int u,int v)
{
    int i=++eo;
    nxt[i]=head[u],vv[i]=v;
    head[u]=i;
}
void dfs(int u,int p)
{
    aux[tin[u]=timer++]=u;
    for(int j=head[u];j;j=nxt[j])if(p-vv[j])dfs(vv[j],u);
}

int findEgg(int n,std::vector<std::pair<int, int> >bridges)
{
    for(int i=1;i<=n;++i)head[i]=eo=timer=0;
    for(auto[u,v]:bridges)link(u,v),link(v,u);
    dfs(1,1);
    int lower=-1,upper=n-1;
    while(upper-lower>1)
    {
        int mid=lower+(upper-lower)/2;
        std::vector<int>q;
        for(int i=0;i<=mid;++i)q.push_back(aux[i]);
        if(q.size()&&query(q))upper=mid;
        else lower=mid;
    }
    return aux[upper];
}

/* int query(std::vector<int> islands) */

• Subtask 1: 40 / 40
• Subtask 2: 40 / 40
• Subtask 3: 20 / 20