C++动态规划求解0-1背包问题

具体内容之后再补_(:з」∠)_ 先把代码贴上

  1 #include <iostream>
  2 #include <fstream>
  3 #include <ctime>
  4 #include <algorithm>
  5 #include <windows.h>
  6 using namespace std;
  7 #define N 10000
  8 
  9 //int w[5] = { 0 , 2 , 3 , 4 , 5 };            //商品的体积2、3、4、5
 10 //int v[5] = { 0 , 3 , 4 , 5 , 6 };            //商品的价值3、4、5、6
 11 //int bagV = 8;                            //背包大小
 12 int dp[N][N];                    //动态规划表
 13 //int item[5];                            //最优解情况
 14 
 15 void findMax(int k,int n,int w[],int v[]) {                    //动态规划
 16     for (int i = 1; i <= k; i++) {
 17         for (int j = 1; j <= n; j++) {
 18             if (j < w[i])
 19                 dp[i][j] = dp[i - 1][j];
 20             else
 21                 dp[i][j] = max(dp[i - 1][j], dp[i - 1][j - w[i]] + v[i]);
 22         }
 23     }
 24 }
 25 
 26 void findWhat(int i, int j,int w[],int v[],int item[]) {                //最优解情况
 27     if (i > 0) {
 28         if (dp[i][j] == dp[i - 1][j]) {
 29             item[i] = 0;
 30             findWhat(i - 1, j,w,v,item);
 31         }
 32         else if (j - w[i] >= 0 && dp[i][j] == dp[i - 1][j - w[i]] + v[i]) {
 33             item[i] = 1;
 34             findWhat(i - 1, j - w[i],w,v,item);
 35         }
 36     }
 37 }
 38 
 39 void print(int k,int n,int item[]) {
 40     /*for (int i = 0; i < k+1; i++) {            //动态规划表输出
 41         for (int j = 0; j < n+1; j++) {
 42             cout << dp[i][j] << ' ';
 43         }
 44         cout << endl;
 45     }
 46     cout << endl;*/
 47     cout <<"The item number that should be put into the backpack is:";
 48     for (int i = 0; i < k+1; i++){            //最优解输出
 49         if(item[i] == 1)
 50           cout << i << ' ';
 51     }
 52     cout << endl;
 53 }
 54 
 55 int main(void)
 56 {
 57     LARGE_INTEGER nFreq;
 58     LARGE_INTEGER nBeginTime;
 59     LARGE_INTEGER nEndTime;
 60     ofstream fout;
 61     double cost;
 62     int i,j,m,n,k;
 63     cout << "Please enter the number of times you want to run the program:";
 64     cin >> m;
 65     //int object_amount[m];
 66     //double runtime[m];
 67     fout.open("backpack.txt",ios::app);
 68     if(!fout){
 69         cerr<<"Can not open file 'backpack.txt' "<<endl;
 70         return -1;
 71     }
 72     fout.setf(ios_base::fixed,ios_base::floatfield);       //防止输出的数字使用科学计数法
 73     srand((unsigned int)time(NULL));
 74     for(i = 0; i < m; i++){
 75         n = rand()%10000;
 76         k = rand()%10000;
 77         //object_amount[i] = k;
 78         fout<<k<<",";
 79         int item[k];
 80         cout << "The " << i+1 << "th test's backpack lattice number is:" << n << endl;
 81         cout << "The " << i+1 << "th test's object amount is:" << k << endl;
 82         int w[k];
 83         int v[k];
 84         memset(dp,0,sizeof(dp));
 85         w[0] = 0;
 86         v[0] = 0;
 87         for(j=1;j<k;j++){
 88             w[j]=rand()%100;
 89             v[j]=rand()%1000;
 90         }
 91         QueryPerformanceFrequency(&nFreq);
 92         QueryPerformanceCounter(&nBeginTime);
 93         findMax(k,n,w,v);
 94         findWhat(k,n,w,v,item);
 95         print(k,n,item);
 96         QueryPerformanceCounter(&nEndTime);
 97         cost=(double)(nEndTime.QuadPart - nBeginTime.QuadPart) / (double)nFreq.QuadPart;
 98         //runtime[i]=cost;
 99         fout<<cost<<endl;
100         cout<<"The running time is:"<<cost<<" s"<<endl;
101     }
102 /*    fout.open("backpack.txt",ios::app);
103     if(!fout){
104         cerr<<"Can not open file 'backpack.txt' "<<endl;
105         return -1;
106     }
107     fout.setf(ios_base::fixed,ios_base::floatfield);       //防止输出的数字使用科学计数法
108     for(i=0;i<m;i++){
109            fout<<object_amount[i]<<","<<runtime[i]<<endl;
110     }*/
111     fout.close();
112     cout<<"Success!"<<endl;
113     return 0;
114 }