Number of common base strings for two strings
Last Updated :
27 Nov, 2022
Given two strings s1 and s2, we need to find number of common base strings of two. A substring of a string s is called base string if repeated concatenation of the substring results in s.
Examples:
Input : s1 = "pqrspqrs"
s2 = "pqrspqrspqrspqrs"
Output : 2
The two common base strings are "pqrs"
and "pqrspqrs".
Input: s1 = "bbb"
s2 = "bb"
Output: 1
There is only one common base string
which is "b".
The maximum possible length of common base string is equal to length of smaller of two strings. So we run a loop that considers all prefixes of smaller string and for every prefix checks if it is a common base.
Below is the implementation of the following approach
C++
// CPP program to count common base strings
// of s1 and s2.
#include <bits/stdc++.h>
using namespace std;
// function for finding common divisor .
bool isCommonBase(string base, string s1,
string s2)
{
// Checking if 'base' is base string
// of 's1'
for (int j = 0; j < s1.length(); ++j)
if (base[j % base.length()] != s1[j])
return false;
// Checking if 'base' is base string
// of 's2'
for (int j = 0; j < s2.length(); ++j)
if (base[j % base.length()] != s2[j])
return false;
return true;
}
int countCommonBases(string s1, string s2) {
int n1 = s1.length(), n2 = s2.length();
int count = 0;
for (int i=1; i<=min(n1, n2); i++)
{
string base = s1.substr(0, i);
if (isCommonBase(base, s1, s2))
count++;
}
return count;
}
// Driver code
int main()
{
string s1 = "pqrspqrs";
string s2 = "pqrspqrspqrspqrs";
cout << countCommonBases(s1, s2) << endl;
return 0;
}
// Java program to count common
// base strings of s1 and s2.
class GFG
{
// function for finding common divisor
static boolean isCommonBase(String base,
String s1,
String s2)
{
// Checking if 'base' is base
// String of 's1'
for (int j = 0; j < s1.length(); ++j)
{
if (base.charAt(j %
base.length()) != s1.charAt(j))
{
return false;
}
}
// Checking if 'base' is base
// String of 's2'
for (int j = 0; j < s2.length(); ++j)
{
if (base.charAt(j %
base.length()) != s2.charAt(j))
{
return false;
}
}
return true;
}
static int countCommonBases(String s1,
String s2)
{
int n1 = s1.length(),
n2 = s2.length();
int count = 0;
for (int i = 1; i <= Math.min(n1, n2); i++)
{
String base = s1.substring(0, i);
if (isCommonBase(base, s1, s2))
{
count++;
}
}
return count;
}
// Driver code
public static void main(String[] args)
{
String s1 = "pqrspqrs";
String s2 = "pqrspqrspqrspqrs";
System.out.println(countCommonBases(s1, s2));
}
}
// This code is contributed by Rajput-JI
# Python 3 program to count common
# base strings of s1 and s2.
# function for finding common divisor .
def isCommonBase(base, s1, s2):
# Checking if 'base' is base
# string of 's1'
for j in range(len(s1)):
if (base[j % len(base)] != s1[j]):
return False
# Checking if 'base' is base
# string of 's2'
for j in range(len(s2)):
if (base[j % len( base)] != s2[j]):
return False
return True
def countCommonBases(s1, s2):
n1 = len(s1)
n2 = len(s2)
count = 0
for i in range(1, min(n1, n2) + 1):
base = s1[0: i]
if (isCommonBase(base, s1, s2)):
count += 1
return count
# Driver code
if __name__ == "__main__":
s1 = "pqrspqrs"
s2 = "pqrspqrspqrspqrs"
print(countCommonBases(s1, s2))
# This code is contributed by ita_c
// C# program to count common base
// strings of s1 and s2.
using System;
class GFG
{
// function for finding common divisor
static bool isCommonBase(String Base,
String s1,
String s2)
{
// Checking if 'base' is base
// String of 's1'
for (int j = 0; j < s1.Length; ++j)
{
if (Base[j % Base.Length] != s1[j])
{
return false;
}
}
// Checking if 'base' is base
// String of 's2'
for (int j = 0; j < s2.Length; ++j)
{
if (Base[j % Base.Length] != s2[j])
{
return false;
}
}
return true;
}
static int countCommonBases(String s1,
String s2)
{
int n1 = s1.Length, n2 = s2.Length;
int count = 0;
for (int i = 1;
i <= Math.Min(n1, n2); i++)
{
String Base = s1.Substring(0, i);
if (isCommonBase(Base, s1, s2))
{
count++;
}
}
return count;
}
// Driver code
public static void Main()
{
String s1 = "pqrspqrs";
String s2 = "pqrspqrspqrspqrs";
Console.Write(countCommonBases(s1, s2));
}
}
// This code is contributed by Rajput-JI
<?php
// PHP program to count common base strings
// of s1 and s2.
// function for finding common divisor .
function isCommonBase($base,$s1, $s2)
{
// Checking if 'base' is base string
// of 's1'
for ($j = 0; $j < strlen($s1); ++$j)
if ($base[$j % strlen($base)] != $s1[$j])
return false;
// Checking if 'base' is base string
// of 's2'
for ($j = 0; $j < strlen($s2); ++$j)
if ($base[$j % strlen($base)] != $s2[$j])
return false;
return true;
}
function countCommonBases($s1, $s2)
{
$n1 = strlen($s1);
$n2 = strlen($s2);
$count = 0;
for ($i = 1; $i <= min($n1, $n2); $i++)
{
$base = substr($s1,0, $i);
if (isCommonBase($base, $s1, $s2))
$count++;
}
return $count;
}
// Driver code
$s1 = "pqrspqrs";
$s2 = "pqrspqrspqrspqrs";
echo countCommonBases($s1, $s2)."\n";
// This code is contributed by mits
?>
<script>
// Javascript program to count common
// base strings of s1 and s2.
// function for finding common divisor
function isCommonBase(base,s1,s2)
{
// Checking if 'base' is base
// String of 's1'
for (let j = 0; j < s1.length; ++j)
{
if (base[j % base.length] != s1[j])
{
return false;
}
}
// Checking if 'base' is base
// String of 's2'
for (let j = 0; j < s2.length; ++j)
{
if (base[j %base.length] != s2[j])
{
return false;
}
}
return true;
}
function countCommonBases(s1,s2)
{
let n1 = s1.length,
n2 = s2.length;
let count = 0;
for (let i = 1; i <= Math.min(n1, n2); i++)
{
let base = s1.substring(0, i);
if (isCommonBase(base, s1, s2))
{
count++;
}
}
return count;
}
// Driver code
let s1 = "pqrspqrs";
let s2 = "pqrspqrspqrspqrs";
document.write(countCommonBases(s1, s2));
// This code is contributed by rag2127
</script>
Time Complexity: O(min(n1, n2) * (n1 + n2))
Auxiliary Space: O(min(n1, n2)), where n1 and n2 are the lengths of the given strings.
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