RT，TLE on #12

#include<bits/stdc++.h>
using namespace std;
const int MAXN=24;
int n;
int x[MAXN+5],y[MAXN+5],dis[MAXN+5][MAXN+5];
int dp[1<<MAXN],pre[1<<MAXN];
pair<int,int>path[1<<MAXN];
inline int dist(int x1,int y1,int x2,int y2)
{
    return (x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
}
int main()
{
    scanf("%d%d",&x[0],&y[0]);
    scanf("%d",&n);
    for(register int i=1;i<=n;i++)
        scanf("%d%d",&x[i],&y[i]);
    for(register int i=0;i<=n;i++)
        for(register int j=0;j<=n;j++)
            dis[i][j]=dist(x[i],y[i],x[j],y[j]);
    memset(pre,-1,sizeof pre);
    memset(dp,0x3f,sizeof dp);
    dp[0]=0;
    for(register int i=0;i<(1<<n);i++)
    {
        if(dp[i]==0x3f3f3f3f)continue;
        for(register int j=1;j<=n;j++)
        {
            if((i>>(j-1))&1)continue;
            for(register int k=1;k<=n;k++)
            {
                if((i>>(k-1))&1)continue;
                int cost=dis[0][j]+dis[j][k]+dis[k][0];
                if(dp[i]+cost<dp[i|(1<<(j-1))|(1<<(k-1))])
                {
                    dp[i|(1<<(j-1))|(1<<(k-1))]=dp[i]+cost;
                    pre[i|(1<<(j-1))|(1<<(k-1))]=i;
                    path[i|(1<<(j-1))|(1<<(k-1))]=make_pair(j,k);
                }
            }
        }
    }
    printf("%d\n",dp[(1<<n)-1]);
    printf("0 ");
    int now=(1<<n)-1;
    while(~pre[now])
    {
        if(path[now].first==path[now].second)printf("%d 0 ",path[now].first);
        else printf("%d %d 0 ",path[now].first,path[now].second);
        now=pre[now];
    }
    return 0;
}
``