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How to decide if a string is a permutation of another string

Given two strings,write an algorithm to decide if one string is permutation of another.

asked Apr 6 by Ranju Kumari

1 Answer


I have solved this problem in C++ by using simple logical approach and with minimum time complexity.

It prints TRUE if a string is permutation of another string and prints FALSE if a string is not a permutation of another.

You can change the values of both strings (basically a char array) then you can check that a string is permutation of another string or not. 

I have hard coded both the strings but you can try it by taking console input too.



using namespace std;

bool isPermutation( char str1[] , char str2[] )
	int myCounter[128] = {0};
	int len1 = 0;
	for( ; str1[len1] != '\0' ; len1++ );
	int len2 = 0;
	for( ; str2[len2] != '\0' ; len2++ );
	if( len1 != len2 )
		return false;
	for( int i = 0 ; i < len1 ; i++ )
	for( int i = 0 ; i < 127 ; i++ )
		if( myCounter[i]!=0 )
			return false;
	return true;

int main()
	char str1[] = "ABCDE";
	char str2[] = "BCDEA";
	if( isPermutation( str1 , str2 ) )
		cout << "TRUE";
		cout << "FALSE";
	return 0;

For any suggestions or problem you can contact on

answered Apr 17 by vipulchasta