int max(int a , int b)
{
    return ((a >= b)?(a):(b));
}

int LSC(char* s1, char* s2 , int len_1  , int len_2 , int i , int j , int ** Hash_Table)
{
    if(i>=len_1 || j>= len_2)
    {
        return 0;
    }
    else if ( Hash_Table[i][j] != 0 ) {
        return Hash_Table[i][j];
    }
    else if(s1[i] == s2[j])
    {
        //rewrite that code to store the value
        int val = 1+LSC(s1 , s2 ,len_1 ,len_2 , i+1 , j+1 , Hash_Table);
        Hash_Table[i][j] = val;
        return val;
    }
    else {
        int val = max(LSC(s1 , s2 , len_1 , len_2  , i+1 , j , Hash_Table) , LSC(s1 , s2 , len_1 , len_2 , i , j+1 , Hash_Table));
        Hash_Table[i][j] = val;
        return val;  
        }
}


/*
 * Complete the 'commonChild' function below.
 *
 * The function is expected to return an INTEGER.
 * The function accepts following parameters:
 *  1. STRING s1
 *  2. STRING s2
 */

int commonChild(char* s1, char* s2) {
    int len_1 = strlen(s1) , len_2 = strlen(s2);
    
    int ** Hash_Table = calloc(len_1, sizeof(int*));
    for (int i = 0; i<len_1 ; i++) {
        Hash_Table[i] = calloc(len_2, sizeof(int));
    }
        
    return LSC(s1, s2 ,len_1 , len_2 , 0 , 0 , Hash_Table);
}