首页 > > 程序设计 > C/C++ >

C++动态规划实现查找最长公共子序列

2019-10-31 16:01:19来源：博客园阅读 ()

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 }