#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

const int N = 20;
const int INF = 0x3f3f3f3f;
int f[1<<N][N], weight[N][N];

int main() {
    int n;
    cin >> n;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            cin >> weight[i][j];
    
    memset(f, 0x3f, sizeof(f));
    f[1][0] = 0; // 初始状态：只访问过0号点
    
    for(int mask = 0; mask < (1<<n); mask++) {
        for(int j = 0; j < n; j++) {
            if((mask >> j) & 1) { // j必须在mask中
                for(int k = 0; k < n; k++) {
                    if(!((mask >> k) & 1)) { // k不能在mask中
                        f[mask|(1<<k)][k] = min(f[mask|(1<<k)][k], f[mask][j] + weight[j][k]);
                    }
                }
            }
        }
    }
    
    cout << f[(1<<n)-1][n-1] << endl;
    return 0;
}

`

#include <bits/stdc++.h> using namespace std; const int N = 520; const int INF = 0x3f3f3f3f; int f[1<<N][N], weight[N][N]; int main() { int n; cin >> n; for(int i = 0; i < n; i++) for(int j = 0; j < n; j++) cin >> weight[i][j];

memset(f, 0x3f, sizeof(f));
f[1][0] = 0; 

for(int mask = 0; mask < (1<<n); mask++) {
    for(int j = 0; j < n; j++) {
        if((mask >> j) & 1) { // 
            for(int k = 0; k < n; k++) {
                if(!((mask >> k) & 1)) { 
                    f[mask|(1<<k)][k] = min(f[mask|(1<<k)][k], f[mask][j] + weight[j][k]);
                }
            }
        }
    }
}

cout << f[(1<<n)-1][n-1] << endl;
return 0;

} //一路向北 `

#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;

const int N = 20;
const int INF = 0x3f3f3f3f;
int f[1<<N][N], weight[N][N];

int main() {
    int n;
    cin >> n;
    for(int i = 0; i < n; i++)
        for(int j = 0; j < n; j++)
            cin >> weight[i][j];
    
    memset(f, 0x3f, sizeof(f));
    f[1][0] = 0; // 初始状态：只访问过0号点
    
    for(int mask = 0; mask < (1<<n); mask++) {
        for(int j = 0; j < n; j++) {
            if((mask >> j) & 1) { // j必须在mask中
                for(int k = 0; k < n; k++) {
                    if(!((mask >> k) & 1)) { // k不能在mask中
                        f[mask|(1<<k)][k] = min(f[mask|(1<<k)][k], f[mask][j] + weight[j][k]);
                    }
                }
            }
        }
    }
    
    cout << f[(1<<n)-1][n-1] << endl;
    return 0;
}