LCS Algorithm Implementation

Dynamic Programming algorithm

#include <iostream>#include<string.h>#include<algorithm>#include<math.h>using namespacestd;#defineMaxstrlen 20intLcs (CharX[],CharY[],intPath[][maxstrlen])//To find the longest common subsequence of the sequence x and Y, the path save route points to facilitate printing of common sub-sequences{    intI, J; intLen1=strlen (x)-1; intLen2=strlen (Y)-1; int**c=New int*[len1+1];  for(i=0; i<=len1; i++) C[i]=New int[len2+1];  for(i=0; i<=len1; i++) c[i][0]=0;  for(i=0; i<=len2; i++) c[0][i]=0;  for(i=1; i<=len1; i++)         for(j=1; j<=len2; J + +)//starting from x[1],y[1]        {            if(x[i]==Y[j]) {C[i][j]=c[i-1][j-1]+1; PATH[I][J]=1; }            Else if(c[i-1][j]>=c[i][j-1]) {C[i][j]=c[i-1][j]; PATH[I][J]=2; }            Else{C[i][j]=c[i][j-1]; PATH[I][J]=3; }                }                returnc[len1][len2];}voidPrintlcs (intIintJCharX[],intPath[][maxstrlen])//print the longest common sub-sequence{    if(i==0|| j==0)        return; if(path[i][j]==1) {Printlcs (i-1, J-1, x, Path); cout<<X[i]; }    Else if(path[i][j]==2) Printlcs (i-1, J, x, Path); ElsePrintlcs (i, J-1, x, Path); }voidMain () {CharA[maxstrlen]; CharB[maxstrlen]; intPath[maxstrlen][maxstrlen]; Gets (a+1);//A[0] Not counting, starting from a[1]Gets (b +1);//B[0] Not counting, starting from b[1]cout<<lcs (A, B, path) <<Endl; cout<<"the longest common subsequence:"; Printlcs (Strlen (a)-1, strlen (b)-1, A, path); cout<<Endl; }

Recursive algorithm

#include <iostream>using namespacestd;#defineMaxstrlen 20//Recursive algorithmintLcs (Char*STR1,Char*str2) {    if(*str1==' /'|| *str2==' /')        return 0; if(*str1==*str2)returnLcs (str1+1, str2+1)+1; Else if(Lcs (str1+1, str2) >lcs (str1, str2+1))        returnLcs (str1+1, STR2); Else        returnLcs (STR1, str2+1); }voidMain () {CharA[maxstrlen]; CharB[maxstrlen];    Gets (a);    Gets (b); cout<<lcs (A, b) <<Endl; }

LCS Algorithm Implementation