You are given two strings str1 and str2. You have to check if the two strings share a common substring.
Examples :
Input : str1 = "HELLO" str2 = "WORLD" Output : YES Explanation : The substrings "O" and "L" are common to both str1 and str2 Input : str1 = "HI" str2 = "ALL" Output : NO Explanation : Because str1 and str2 have no common substrings
A basic approach runs in O(n^2), where we compare every character of string 1 with every character of string 2 and replace every matched character with a “_” and set flag variable as true.
An efficient approach works in O(n). We basically need to check if there is a common character or not. We create a vector of size 26 for alphabets and initialize them as 0. For every character in string 1 we increment vector index of that character eg: v[s1[i]-‘a’]++, for every character of string 2 we check vector for the common characters if v[s2[i]-‘a’] > 0 then set flag = true and v[s2[i]-‘a’]– such that one character of string 2 is compared with only one character of string 1.
Implementation:
// CPP program to check if two strings have // common substring #include <bits/stdc++.h> using namespace std;
const int MAX_CHAR = 26;
// function to return true if strings have // common substring and no if strings have // no common substring bool twoStrings(string s1, string s2) {
// vector for storing character occurrences
vector< bool > v(MAX_CHAR, 0);
// increment vector index for every
// character of str1
for ( int i = 0; i < s1.length(); i++)
v[s1[i] - 'a' ] = true ;
// checking common substring of str2 in str1
for ( int i = 0; i < s2.length(); i++)
if (v[s2[i] - 'a' ])
return true ;
return false ;
} // driver program int main() {
string str1 = "hello" ;
string str2 = "world" ;
if (twoStrings(str1, str2))
cout << "Yes" ;
else
cout << "No" ;
return 0;
} |
// Java program to check if two strings have // common substring import java.util.Arrays;
class GFG
{ static int MAX_CHAR = 26 ;
// function to return true if strings have
// common substring and no if strings have
// no common substring
static boolean twoStrings(String s1, String s2)
{
// vector for storing character occurrences
boolean v[]= new boolean [MAX_CHAR];
Arrays.fill(v, false );
// increment vector index for every
// character of str1
for ( int i = 0 ; i < s1.length(); i++)
v[s1.charAt(i) - 'a' ] = true ;
// checking common substring of str2 in str1
for ( int i = 0 ; i < s2.length(); i++)
if (v[s2.charAt(i) - 'a' ])
return true ;
return false ;
}
// Driver code
public static void main (String[] args)
{
String str1 = "hello" ;
String str2 = "world" ;
if (twoStrings(str1, str2))
System.out.print( "Yes" );
else
System.out.print( "No" );
}
} // This code is contributed by Anant Agarwal. |
# Python3 code to implement the approach # python program to check if two strings have # common substring MAX_CHAR = 26
# function to return true if strings have # common substring and no if strings have # no common substring def twoStrings(s1, s2):
# vector for storing character occurrences
v = [ 0 for i in range (MAX_CHAR)]
# increment vector index for every
# character of str1
for i in range ( len (s1)):
v[ ord (s1[i]) - ord ( 'a' )] = True
# checking common substring of str2 in str1
for i in range ( len (s2)):
if v[ ord (s2[i]) - ord ( 'a' )]:
return True
return False
# driver program str1 = "hello"
str2 = "world"
if twoStrings(str1, str2):
print ( "Yes" )
else :
print ( "No" )
# This code is contributed by phasing17 |
// C# program to check if two // strings have common substring using System;
class GFG
{ static int MAX_CHAR = 26;
// function to return true if strings have
// common substring and no if strings have
// no common substring
static bool twoStrings(String s1, String s2)
{
// vector for storing character occurrences
bool []v = new bool [MAX_CHAR];
// Arrays.fill(v,false);
for ( int i = 0; i < MAX_CHAR; i++)
v[i]= false ;
// increment vector index for
// every character of str1
for ( int i = 0; i < s1.Length; i++)
v[s1[i] - 'a' ] = true ;
// checking common substring of str2 in str1
for ( int i = 0; i < s2.Length; i++)
if (v[s2[i] - 'a' ])
return true ;
return false ;
}
// Driver code
public static void Main ()
{
String str1 = "hello" ;
String str2 = "world" ;
if (twoStrings(str1, str2))
Console.Write( "Yes" );
else
Console.Write( "No" );
}
} // This code is contributed by nitin mittal. |
<script> // javascript program to check if two strings have // common substring var MAX_CHAR = 26;
// function to return true if strings have // common substring and no if strings have // no common substring function twoStrings(s1, s2) {
// vector for storing character occurrences
var v = Array(MAX_CHAR).fill(0);
// increment vector index for every
// character of str1
for ( var i = 0; i < s1.length; i++)
v[s1[i] - 'a' ] = true ;
// checking common substring of str2 in str1
for ( var i = 0; i < s2.length; i++)
if (v[s2[i] - 'a' ])
return true ;
return false ;
} // driver program var str1 = "hello" ;
var str2 = "world" ;
if (twoStrings(str1, str2))
document.write( "Yes" );
else document.write( "No" );
// This code is contributed by rutvik_56. </script> |
Yes
Time Complexity : O(n)
Auxiliary Space: O(1)