Total character pairs from two strings, with equal number of set bits in their ascii value
Given two strings s1 and s2. The task is to take one character from first string and one character from second string and check if the ASCII values of both the character have same number of set bits. Print the total number of such pairs.
Examples:
Input: s1 = “xcd”, s2 = “swa”
Output: 1
Only valid pair is (d, a) with ASCII values as 100 and 97 respectively.
Both of which contains 3 set bits.
Input: s1 = “geeks”, s2 = “forgeeks”
Output: 17
Approach:
- Make two arrays arr1 and arr2 of size 6 with all values initialized to 0 to store the frequency of number of set bits. Since maximum number of set bits in lower case alphabets is 6.
- Traverse the string s1, and find the ascii value of each character. Store the frequency of number of set bits of each ascii value in a array arr1. (For example, if there are 3 characters with 4 set bits, then store 3 at arr[4])
- Do the similar operation for string s2 and store its value in another array arr2.
- Initialize a count variable with 0.
- For total number of pairs, keep on adding (arr1[i] * arr2[i]) in count variable for all valid values of i.
Below is the implementation of the above approach:
C++
// C++ implementation of the approach #include <bits/stdc++.h> using namespace std; // Function to return the count of valid pairs int totalPairs(string s1, string s2) { int count = 0; int arr1[7], arr2[7]; // Initialise both arrays with 0 for (int i = 1; i <= 6; i++) { arr1[i] = 0; arr2[i] = 0; } // Store frequency of number of set bits for s1 for (int i = 0; i < s1.length(); i++) { int set_bits = __builtin_popcount((int)s1[i]); arr1[set_bits]++; } // Store frequency of number of set bits for s2 for (int i = 0; i < s2.length(); i++) { int set_bits = __builtin_popcount((int)s2[i]); arr2[set_bits]++; } // Calculate total pairs for (int i = 1; i <= 6; i++) count += (arr1[i] * arr2[i]); // Return the count of valid pairs return count; } // Driver code int main() { string s1 = "geeks"; string s2 = "forgeeks"; cout << totalPairs(s1, s2); return 0; } |
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Java
// Java implementation of the approach class GFG { // Function to return the count of valid pairs static int totalPairs(String s1, String s2) { int count = 0; int[] arr1 = new int[7]; int[] arr2 = new int[7]; // Default Initialise both arrays 0 // Store frequency of number of set bits for s1 for (int i = 0; i < s1.length(); i++) { int set_bits = Integer.bitCount(s1.charAt(i)); arr1[set_bits]++; } // Store frequency of number of set bits for s2 for (int i = 0; i < s2.length(); i++) { int set_bits = Integer.bitCount(s2.charAt(i)); arr2[set_bits]++; } // Calculate total pairs for (int i = 1; i <= 6; i++) { count += (arr1[i] * arr2[i]); } // Return the count of valid pairs return count; } // Driver code public static void main(String[] args) { String s1 = "geeks"; String s2 = "forgeeks"; System.out.println(totalPairs(s1, s2)); } } // This code has been contributed by 29AjayKumar |
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Python3
# Python3 implementation of the approach # Function to get no of set bits in binary # representation of positive integer n def countSetBits(n): count = 0 while (n): count += n & 1 n >>= 1 return count # Function to return the count # of valid pairs def totalPairs(s1, s2) : count = 0; arr1 = [0] * 7; arr2 = [0] * 7; # Store frequency of number # of set bits for s1 for i in range(len(s1)) : set_bits = countSetBits(ord(s1[i])) arr1[set_bits] += 1; # Store frequency of number of # set bits for s2 for i in range(len(s2)) : set_bits = countSetBits(ord(s2[i])); arr2[set_bits] += 1; # Calculate total pairs for i in range(1, 7) : count += (arr1[i] * arr2[i]); # Return the count of valid pairs return count; # Driver code if __name__ == "__main__" : s1 = "geeks"; s2 = "forgeeks"; print(totalPairs(s1, s2)); # This code is contributed by Ryuga |
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C#
// C# implementation of the approach using System; using System.Linq; class GFG { // Function to return the count of valid pairs static int totalPairs(string s1, string s2) { int count = 0; int[] arr1 = new int[7]; int[] arr2 = new int[7]; // Default Initialise both arrays 0 // Store frequency of number of set bits for s1 for (int i = 0; i < s1.Length; i++) { int set_bits = Convert.ToString((int)s1[i], 2).Count(c => c == '1'); arr1[set_bits]++; } // Store frequency of number of set bits for s2 for (int i = 0; i < s2.Length; i++) { int set_bits = Convert.ToString((int)s2[i], 2).Count(c => c == '1'); arr2[set_bits]++; } // Calculate total pairs for (int i = 1; i <= 6; i++) count += (arr1[i] * arr2[i]); // Return the count of valid pairs return count; } // Driver code static void Main() { string s1 = "geeks"; string s2 = "forgeeks"; Console.WriteLine(totalPairs(s1, s2)); } } // This code is contributed by chandan_jnu |
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Output:
17
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