poj3311_状压dp+Dijkstra

  题目链接：http://poj.org/problem?id=3311

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#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cstdlib>
#include <cmath>
#include <set>
#include <map>
#include <queue>
#include <vector>
#define INF 0x3f3f3f3f
using namespace std;

const int N = 11, M = 1 << N;
int dp[M][N], a[12][12], n, used[12], dist[12][12];
void djs()
{
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            dist[i][j] = INF;
    for(int i = 0; i < n; i++)
    {
        memset(used, 0, sizeof(used));
        used[i] = 1;
        for(int j = 0; j < n; j++)
            dist[i][j] = a[i][j];
        while(1)
        {
            int u = -1, MIN = INF;
            for(int j = 0; j < n; j++)
            {
                if(!used[j] && dist[i][j] < MIN)
                {
                    u = j; 
                    MIN = dist[i][j];
                }
            }
            if(u == -1)
                break;
            used[u] = 1;
            for(int j = 0; j < n; j++)
                dist[i][j] = min(dist[i][j], dist[i][u] + a[u][j]);
        }
    }
}
int main()
{
    while(~scanf("%d", &n) && n)
    {
        n++;
        for(int i = 0; i < n; i++)
            for(int j = 0; j < n; j++)
                scanf("%d", &a[i][j]);
        djs();
        for(int i = 0; i < (1 << n); i++)
            for(int j = 0; j < n; j++)
                dp[i][j] = INF;
        dp[1][0] = 0;
        for(int i = 1; i < (1 << n); i++)
        {
            for(int j = 0; j < n; j++)
            {
                if(i & (1 << j))
                {
                    for(int k = 0; k < n; k++)
                    {
                        int next = i | (1 << k);
                        dp[next][k] = min(dp[i][j] + dist[j][k], dp[next][k]);
                    }
                }
            }
        }
        int x = (1 << n) - 1, res = INF;
        for(int i = 1; i < n; i++)
        {
            res = min(dp[x][i] + dist[i][0], res);
        }
        printf("%d
", res);
    }
    return 0;
}