#include <iostream>#include <ctime>#include <boost/timer/timer.hpp>using namespace std;using namespace boost::timer;void lcs_length(char *a,int m,char *b,int n,int **c)//最长公共子序列{//自底向上法for(int i=1;i<=m;++i){for(int j=1;j<=n;++j){if(a[i-1]==b[j-1]){c[i][j]=c[i-1][j-1]+1;}else if(c[i-1][j]>=c[i][j-1]){c[i][j]=c[i-1][j];}else{c[i][j]=c[i][j-1];}}}}int memo_lcs_length(char *a,int m,char *b,int n,int **c){//递归的，自上而下if(c[m][n]!=numeric_limits<int>::min())return c[m][n];if(a[m-1]==b[n-1]){c[m][n]=memo_lcs_length(a,m-1,b,n-1,c)+1;}else{c[m][n]=max(memo_lcs_length(a,m-1,b,n,c),memo_lcs_length(a,m,b,n-1,c));}return c[m][n];}void print_lcs_recursive(int *a,int *b,int **c,int m,int n){if(m==0 || n==0)return;if((c[m][n]==c[m-1][n-1]+1)&& c[m][n]!=c[m-1][n] &&c[m][n]!=c[m][n-1]){print_lcs_recursive(a,b,c,m-1,n-1);cout<<a[m-1]<<"\t";}else if(c[m-1][n]>c[m][n-1]){print_lcs_recursive(a,b,c,m-1,n);}else{print_lcs_recursive(a,b,c,m,n-1);}}void print_lcs_iterator(int *a,int *b,int **c,int m,int n){while (m!=0 && n!=0){if((c[m][n]==c[m-1][n-1]+1)&& c[m][n]!=c[m-1][n] &&c[m][n]!=c[m][n-1]){m-=1;n-=1;cout<<a[m]<<"\t";}else if(c[m][n]==c[m-1][n]){m-=1;}else{n-=1;}}}int main(){srand((unsigned)time(NULL));int m,n;while (m=rand()%53,m<30);while(n=rand()%53,n<30);m=10000,n=10500;/*m=8,n=9;char a[8]={'1','0','0','1','0','1','0','1'};char b[9]={'0','1','0','1','1','0','1','1','0'};*/char *a=new char[m];char *b=new char[n];for(int i=0;i<m;++i){//随机生成字符数组if(rand()%2)a[i]=rand()%26+'A';elsea[i]=rand()%26+'a';}for(int i=0;i<n;++i){if(rand()%2)b[i]=rand()%26+'A';elseb[i]=rand()%26+'a';}/*for(int i=0;i<m;++i){cout<<a[i]<<" ";}cout<<endl;for(int i=0;i<n;++i){cout<<b[i]<<" ";}cout<<endl;*/int **c=new int *[m+1];for(int i=0;i<m+1;++i){c[i]=new int [n+1];}for(int i=0;i<m+1;++i){c[i][0]=0;}for(int j=0;j<n+1;++j){c[0][j]=0;}for(int i=1;i<m+1;++i){for(int j=1;j<n+1;++j){c[i][j]=numeric_limits<int>::min();}}cpu_timer t1;t1.start();lcs_length(a,m,b,n,c);t1.stop();cout<<t1.format();/*for(int i=0;i<m+1;++i){for(int j=0;j<n+1;++j){cout<<c[i][j]<<" ";}cout<<endl;}*/cout<<c[m][n]<<endl;print_lcs_recursive(a,b,c,m,n);cout<<endl;for(int i=0;i<m+1;++i){c[i][0]=0;}for(int j=0;j<n+1;++j){c[0][j]=0;}for(int i=1;i<m+1;++i){for(int j=1;j<n+1;++j){c[i][j]=numeric_limits<int>::min();}}cpu_timer t2;t2.start();memo_lcs_length(a,m,b,n,c);t2.stop();cout<<t2.format();/*for(int i=0;i<m+1;++i){for(int j=0;j<n+1;++j){cout<<c[i][j]<<" ";}cout<<endl;}*/cout<<c[m][n]<<endl;print_lcs_recursive(a,b,c,m,n);cout<<endl;delete[]a;delete[]b;delete[]c;}
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