Count common characters in two strings | C ++ implementation of the approach ; Function to return the count of valid indices pairs ; To store the frequencies of characters of string s1 and s2 ; To store the count of valid pairs ; Update the frequencies of the characters of string s1 ; Update the frequencies of the characters of string s2 ; Find the count of valid pairs ; Driver code
#include <bits/stdc++.h> NEW_LINE using namespace std ; int countPairs ( string s1 , int n1 , string s2 , int n2 ) { int freq1 [ 26 ] = { 0 } ; int freq2 [ 26 ] = { 0 } ; int i , count = 0 ; for ( i = 0 ; i < n1 ; i ++ ) freq1 [ s1 [ i ] - ' a ' ] ++ ; for ( i = 0 ; i < n2 ; i ++ ) freq2 [ s2 [ i ] - ' a ' ] ++ ; for ( i = 0 ; i < 26 ; i ++ ) count += ( min ( freq1 [ i ] , freq2 [ i ] ) ) ; return count ; } int main ( ) { string s1 = " geeksforgeeks " , s2 = " platformforgeeks " ; int n1 = s1 . length ( ) , n2 = s2 . length ( ) ; cout << countPairs ( s1 , n1 , s2 , n2 ) ; return 0 ; }