8C-动态规划

#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <sstream>
#include <fstream>
#include <cmath>
#include <cstdlib>
#include <cstdio>
#include <cstring>
#include <complex>
using namespace std;

typedef complex<int> point;
typedef pair<int,int> pii;


unsigned int dp[1<<24];
point origin;
int x,y;
int n;
point pts[30];
int dist[30][30];
int checkDist[30][30];

int distancee(int i, int j) {
    return norm(pts[i]-pts[j]);
}

int checkDistance(int i, int j) {
    return dist[i][n]+dist[i][j]+dist[j][n];
}

void precompute() {
    int i,j;
    for(i=0;i<=n;++i) for(j=i;j<=n;++j) {
        dist[i][j] = distancee(i,j);
        dist[j][i] = dist[i][j];
    }
    for(i=0;i<n;++i) for(j=i;j<n;++j) {
        checkDist[i][j] = checkDistance(i,j);
        checkDist[j][i] = checkDist[i][j];
    }
}

int f(unsigned int mask) {
    if(dp[mask]!=-1)return dp[mask];
    if(mask==(1<<n)-1) {
        dp[mask] = 0;
        return 0;
    }
    int i,j;
    int ret = -1;
    int tmp;
    for(i=0;i<n;++i) if( !(mask & (1<<i)) ) {
        tmp = f(mask | (1<<i));
        tmp += 2*dist[n][i];
        if(tmp<ret || ret==-1) {
            ret = tmp;
        }
        unsigned int tmpMask = mask;
        for(j=i+1;j<n;++j) if( !(mask & (1<<j)) ) {
            tmpMask = mask;
            tmpMask |= (1<<j);
            tmpMask |= (1<<i);
            tmp = f(tmpMask);
            tmp += checkDist[i][j];
            if(tmp<ret || ret==-1) {
                ret = tmp;
            }
        }
        break;
    }
    dp[mask] = ret;
    return ret;
}

int main() {
    cin>>x>>y;
    origin = point(x,y);
    cin>>n;
    int i,j;
    for(i=0;i<n;++i) {
        cin>>x>>y;
        pts[i] = point(x,y);
    }
    pts[n] = origin;
    precompute();
    memset(dp,-1,sizeof dp);
    int ret = f(0);
    cout<<ret<<endl;
    ostringstream sout;
    sout<<"0";
    unsigned int mask = 0;
    int tmp;
    while(mask != (1<<n)-1) {
        for(i=0;i<n;++i) if(!(mask & (1<<i))) {
            tmp = dp[mask | (1<<i)];
            tmp += 2*dist[i][n];
            if(tmp==dp[mask]) {
                sout<<" "<<i+1<<" 0";
                mask = mask | (1<<i);
            }
            else {
                unsigned int tmpMask;
                for(j=i+1;j<n;++j) if(!(mask & (1<<j))) {
                    tmpMask = mask;
                    tmpMask |= (1<<i);
                    tmpMask |= (1<<j);
                    tmp = dp[tmpMask];
                    tmp += checkDist[i][j];
                    if(tmp==dp[mask]) {
                        sout<<" "<<i+1<<" "<<j+1<<" 0";
                        mask = tmpMask;
                        break;
                    }
                }
            }
            break;
        }
    }
    cout<<sout.str()<<endl;
    return 0;
}