C++动态规划实现查找最长公共子序列

具体内容之后再补_(:з」∠)_先贴代码

  1 #include<cstdio>
  2 #include<cstring>
  3 #include<stack>
  4 #include<ctime>
  5 #include<iostream>
  6 #include<fstream>
  7 #include<algorithm>
  8 #include<windows.h>
  9 using namespace std;
 10 large_integer nfreq;//large_integer在64位系统中是longlong，在32位系统中是高低两个32位的long，在windows.h中通过预编译宏作定义
 11 large_integer nbegintime;//记录开始时的计数器的值
 12 large_integer nendtime;//记录停止时的计数器的值
 13 #define n 10000
 14 //const int size_char = 10000; //生成32 + 1位c style字符串
 15 const char cch[] = "_0123456789abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz_";
 16 int dp[n][n];
 17 char c;
 18 int main(void)
 19 {
 20     //char a[n];
 21     //char b[n];
 22     //char a[size_char+2];
 23     //char b[size_char+2];
 24     ofstream fout;
 25     int m = 0,i = 0;
 26     int size_char;
 27     cout<<"please enter the number of times you want to run the program:";        //输入程序运行次数
 28     cin>>m;
 29     //int size[m];
 30     double cost;
 31     //double runtime[m];
 32     srand((unsigned)time(null));
 33     fout.open("data.txt",ios::app);
 34     if(!fout){
 35         cerr<<"can not open file 'data.txt' "<<endl;
 36         return -1;
 37     }
 38     fout.setf(ios_base::fixed,ios_base::floatfield);   //防止输出的数字使用科学计数法
 39     for(i = 0; i < m; i++){
 40         //size_char=10000+rand_max*(rand()%300)+rand();           //rand_max=32767,随机生成数据量
 41         size_char = rand() % 10000;
 42         fout<<size_char<<",";
 43         // size[i]=size_char;                                      //限定数据规模为10000~9872867
 44         char a[size_char + 1] = {'\0'};
 45         char b[size_char + 1] = {'\0'};
 46         cout<<"☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆the "<<i+1<<"th test's string size is:"<<size_char<<"☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆☆"<<endl;
 47         for (int i = 0; i < size_char; ++i){
 48             int x = rand() / (rand_max / (sizeof(cch) - 1));
 49             a[i] = cch[x];
 50         }
 51         cout<<"the first random sting is:" <<a <<endl;
 52         for (int i = 0; i < size_char; ++i){
 53             int x = rand() / (rand_max / (sizeof(cch) - 1));
 54             b[i] = cch[x];
 55         }
 56         cout<<"the second random string is:" <<b <<endl;
 57         cout<<"the longest common subsequence is:";
 58         queryperformancefrequency(&nfreq);//获取系统时钟频率
 59         queryperformancecounter(&nbegintime);//获取开始时刻计数值
 60         int la=strlen(a);
 61         int lb=strlen(b);
 62         memset(dp,0,sizeof(dp));
 63         for(int i=1; i<=la; i++){
 64             for(int j=1; j<=lb; j++){
 65                 if(a[i-1]==b[j-1])
 66                     dp[i][j]=dp[i-1][j-1]+1;
 67                 else
 68                     dp[i][j]=max(dp[i-1][j],dp[i][j-1]);
 69             }
 70         }
 71         int i=la,j=lb;
 72         stack<char>s;
 73         while(dp[i][j]){
 74             if(dp[i][j]==dp[i-1][j]){//来自于左方向
 75                 i--;
 76             }
 77             else if(dp[i][j]==dp[i][j-1]){//来自于上方向
 78                 j--;
 79             }
 80             else if(dp[i][j]>dp[i-1][j-1]){//来自于左上方向
 81                 i--;
 82                 j--;
 83                 s.push(a[i]);         //压栈以便倒序输出
 84         }
 85     }
 86     while(!s.empty())
 87     {
 88         c=s.top();
 89         printf("%c",c);
 90         s.pop();
 91     }
 92     cout<<endl;
 93     queryperformancecounter(&nendtime);//获取停止时刻计数值
 94     cost=(double)(nendtime.quadpart - nbegintime.quadpart) / (double)nfreq.quadpart;
 95     fout<<cost<<endl;
 96     //runtime[i]=cost;
 97     cout<<"the running time is："<<cost<<" s"<<endl;
 98     }
 99     fout.close();
100     cout<<"success!"<<endl;
101     return 0;
102 }