主要思路就是通过dp数组记录状态进行剪枝,不明白为什么wa了,求条
#include<bits/stdc++.h>
#define int long long
#define ll long long
using namespace std;
const int N = 15, inf = 200000000000;
int n, m;
int g[N][N];
bool in[N];
ll ans = inf;
int dep[N];
int dp[1 << N];
void dfs(int statue, int cnt, int sum)
{
if(sum >= ans || dp[statue] <= sum)
return ;
dp[statue] = sum;
if(cnt >= n)
{
ans = sum;
return ;
}
for(int i = 0; i < n; i ++)//由集合里的哪个连出去
{
int x = i;
if(!in[x])continue;
for(int y = 0; y < n; y ++)
{
int w = g[x][y];
if(w > inf || in[y] || y == x)continue;
dep[y] = dep[x] + 1;
in[y] = 1;
dfs(statue ^ (1 << y), cnt + 1, sum + w * dep[x]);
in[y] =0 ;
dep[y] = 0;
}
}
}
signed main()
{
cin >> n >> m;
memset(g, 127, sizeof g);
for(int i = 1; i <= m; i ++)
{
int u, v, w;
cin >> u >> v >> w;
u --;
v --;
g[u][v] = min(g[u][v], w);
g[v][u] = min(g[v][u], w);
}
for(int i = 0; i < n; i ++)
g[i][i] = 0;
for(int i = 0; i < n; i ++)
{
memset(dp, 127, sizeof dp);
in[i] = 1;
dep[i] = 1;
dfs(1 << i, 1, 0);
dep[i] = 0;
in[i] = 0;
}
cout << ans << endl;
return 0;
}