USACO 2.1 Healthy Holsteins (holstein)

//Main Idear//The key point of this problem is "Cows can be fed at most one scoop of any feed type"//Then the max conbination of feeds is 2^15 = 32768,because for each feed type//we can choose to add it or not.So the brute force is acceptable. /*ID: haolink1PROG: holsteinLANG: C++*///#include <iostream>#include <fstream>#include <vector>using namespace std;const short max_vitamins = 25;const short max_feeds = 15;short feeds_vitamins[max_feeds][max_vitamins];void CopyArray(short* first,short* second,short len);bool AllNoPositive(short* element,short len);int main(){    ifstream fin("holstein.in");    short vitamins_num = 0;    fin >> vitamins_num;     short* target_vitamins = new short[vitamins_num];    for(short i = 0; i < vitamins_num; i++){        fin >> target_vitamins[i];    }    short feeds_num = 0;    fin >> feeds_num;    for(short i = 0; i < feeds_num; i++){        for(short j = 0; j < vitamins_num; j++){            fin >> feeds_vitamins[i][j];        }    }    int  total_combination = 1;    for(short i = 0; i < feeds_num; i++){       total_combination *= 2;     }    short* temp_vitamins = new short[vitamins_num];    short min_type = feeds_num+1;    vector<short> feeds;    //Note the variable i's type can't be short,because if i want to go out the its loop,    //its value must reach 32768    for(int i = 1; i < total_combination; i++){        short checker = 1;        CopyArray(target_vitamins,temp_vitamins,vitamins_num);        for(short j = 0;j < feeds_num; j++){            //Note this is a good way to express whether we choose one feed type            //by operator &            if(i&(checker<<j)){                for(short k = 0; k < vitamins_num; k++){                   temp_vitamins[k] -= feeds_vitamins[j][k];                 }                if(AllNoPositive(temp_vitamins,vitamins_num)){                    short total_type = 0;                    for(short m = 0; m < feeds_num; m++){                        if(i & (checker << m)){                            total_type++;                        }                    }                    if(total_type < min_type){                        min_type = total_type;                        feeds.clear();                        for(short m = 0; m < feeds_num; m++){                            if(i & (checker << m)){                                feeds.push_back(m);                            }                        }                    }                 }            }        }     }     ofstream fout("holstein.out");    fout<<min_type<<" ";    short feeds_size = feeds.size();    for(short m = 0; m < feeds_size-1; m++){        fout<<feeds[m]+1<<" ";    }    if(feeds_size > 0)        fout<<feeds[feeds_size - 1]+1<<endl;    delete[] target_vitamins;    return 0;}void CopyArray(short* first,short* second,short len){    for(short i = 0; i < len; i++){        second[i] = first[i];    }}bool AllNoPositive(short* element,short len){    for(short i = 0; i < len; i++){        if(element[i] > 0 ){            return false;        }    }    return true;}