LongestCommonSubString.java

public class LongestCommonSubString {

	public static int find(char [] A, char [] B){
		int [][]LCS = new int [A.length+1][B.length+1];
		// if A is null then LCS of A, B =0
		for(int i=0;i<=B.length;i++){
			LCS[0][i]=0;
		}
		
		// if B is null then LCS of A, B =0
		for(int i=0;i<=A.length;i++){ 
			LCS[i][0]=0;
		}
		
		//fill the rest of the matrix
		for(int i=1;i<=A.length;i++){
			for(int j=1;j<=B.length;j++){
				if(A[i-1]==B[j-1]){
					LCS[i][j] =  LCS[i-1][j-1] +1;
				}else{
					LCS[i][j] = 0;					
				}
			}
		}	
		int result = -1;
		for(int i=0;i<=A.length;i++){
			for(int j=0;j<=B.length;j++){
				if(result<LCS[i][j]){
					result = LCS[i][j];
				}
			}
		}	
		return result;
	}
	public static void main(String[] args) {
		String A = "tutorialhorizon";
		String B = "dynamictutorialProgramming";		
		System.out.println("LCS length : " + find(A.toCharArray(), B.toCharArray()));
	}
}