KiloManX SRM 181 div1 Level 3

#include <algorithm>
#include <ctime>
#include <iostream>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cctype>
#include <cmath>

using namespace std;
typedef unsigned long long LL;
#define FOR(k,a,b) for(int k(a); k < (b); ++k)
#define FORD(k,a,b) for(int k(a-1); k >= (b); --k)
#define REP(k,a) for(int k=0; k < (a); ++k)
#define ABS(a) ((a)>0?(a):-(a))

class KiloManX {
    public:
    int leastShots(vector <string> damageChart, vector <int> bossHealth)
    {
        int n=damageChart.size();
        vector<vector<int> > dc(n,vector<int> (n));
        REP(i,n)
        REP(j,n)
        {
            dc[i][j]=damageChart[i][j]-'0';
        }
        vector<int> dp((1<<n),100000000);
        dp[0]=0;
        REP(i,1<<n)
        {
            REP(j,n)
            if((1<<j) & ~i)
            {
                int best=1;
                REP(k,n)
                if(((1<<k)&i) && (dc[k][j]>best))
                {
                    best=dc[k][j];
                }
                dp[i|(1<<j)]=min(dp[i|(1<<j)],dp[i]+(bossHealth[j]+best-1)/best);
            }
        }
        return dp.back();
    }
};