Codeforces Round #321 (Div. 2) D Kefa and Dishes

#include<bits/stdc++.h>
using namespace std;


typedef pair<int,int> nd;
typedef long long ll;
#define fi first
#define se second
int n,m,a[18];
int g[18][18];
const int maxs = 1<<18;
ll d[maxs][18];
bool vis[maxs][18];
inline int bitcount(int s)
{
    int ct = 0;
    while(s){
        ct += s&1;
        s >>= 1;
    }
    return ct;
}

ll spfa()
{
    queue<nd>q;
    ll ans = 0;
    for(int i = 0; i < n; i++){
        q.push(nd(1<<i,i));
        d[1<<i][i] = a[i];
        vis[1<<i][i] = true;
    }
    while(q.size()){
        nd &u = q.front(); vis[u.fi][u.se] = false;
        int bc = bitcount(u.fi);
        if(bc == m) { ans = max(ans,d[u.fi][u.se]); q.pop(); continue; }
        for(int i = 0; i < n; i++){
            if(1&(u.fi>>i)) continue;
            int ns = 1<<i|u.fi;
            if(d[ns][i] < d[u.fi][u.se] + g[u.se][i] + a[i]){
                d[ns][i] = d[u.fi][u.se] + g[u.se][i] + a[i];
                if(!vis[ns][i]){
                    q.push(nd(ns,i)); vis[ns][i] = true;
                }
            }
        }
        q.pop();
    }
    return ans;
}
int main()
{
    //freopen("in.txt","r",stdin);
    int k;scanf("%d%d%d",&n,&m,&k);
    for(int i = 0; i < n; i++){
        scanf("%d",a+i);
    }
    while(k--){
        int x,y; scanf("%d%d",&x,&y);
        scanf("%d",g[x-1]+y-1);
    }
    printf("%I64d",spfa());
    return 0;
}