HDU 4385

状态DP

#include<iostream>
#include<cstdio>
#define MAXN 23
#define MAXM 1500000
using namespace std;
int x,y;
int bx[MAXN],by[MAXN];
int dis[MAXN][MAXN];
int dp[MAXM];
int way[MAXM];
int n;
int num;

void get_dp(int x)
{
    if (dp[x] != 0)return ;
    for (int i(0); i<n; ++i) {
        int k = 1<<i;
        if (k > x)break;
        if (x&k) {
            if (dp[x^k] == 0)get_dp(x^k);
            if (dp[x] == 0) {
                dp[x] = dp[x^k] + 2*dis[i+1][0];
                way[x] = x^k;
            } else {
                if (dp[x] > dp[x^k] + 2*dis[i+1][0]) {
                    dp[x] = dp[x^k] + 2*dis[i+1][0];
                    way[x] = x^k;          
                }
            }
            for (int j(i+1); j<n; ++j) {
                int kk = 1<<j;
                if (kk > x)break;
                if (x&kk) {
                    if (dp[x^k^kk] == 0)get_dp(x^k^kk);
                    if (dp[x] > dp[x^k^kk] + dis[i+1][0] + dis[j+1][0] + dis[i+1][j+1]) {
                        dp[x] = dp[x^k^kk] + dis[i+1][0] + dis[j+1][0] + dis[i+1][j+1];
                        way[x] = x^k^kk;          
                    }
                }
            }
        }
    }
    return ;
}

void out(int x)  
{  
    int t(x^way[x]), i(1);  
    while (t != 0) {  
        if (t&1) {  
            num++;  
            if (num < n)cout<<i<<" ";  
            else cout<<i<<endl;  
        }  
        i++;  
        t>>=1;  
    }  
    if (way[x] > 0)out(way[x]);  
} 

int main()
{
    int t;
    scanf("%d",&t);
    for (int i(1); i<=t; ++i) {
        num = 0;
        cout<<"Case "<<i<<":"<<endl;
        memset(dp,0,sizeof(dp));
        scanf("%d%d",&x,&y);
        scanf("%d",&n);
        for (int j(1); j<=n; ++j) {
            scanf("%d%d",&bx[j],&by[j]);
        }
        for (int j(1); j<=n; ++j) {
            for (int k(j+1); k<=n; ++k) {
                dis[j][k] = dis[k][j] = (bx[k] - bx[j])*(bx[k] - bx[j]) + (by[k] - by[j])*(by[k] - by[j]);
            }
        }
        for (int j(1); j<=n; ++j) {
            dis[j][0] = (bx[j] - x)*(bx[j] - x) + (by[j] - y)*(by[j] - y);    
        }        
        get_dp((1<<n)-1);
        cout<<dp[(1<<n)-1]<<endl;
        out((1<<n)-1);        
    }
    return 0;
}