Minimize the number of swaps of characters with the same index so that the sum of the ASCII values ​​of the characters in the two strings is an odd number

In this article, we delve into a fascinating problem of string manipulation and character encoding in computer science. The current task is to minimize the number of swaps between identically indexed characters of two strings such that the sum of the ASCII values ​​of the characters in the two strings is an odd number. We solve this problem using C, a powerful and versatile programming language favored by many software developers.

Understanding ASCII

ASCII is the abbreviation of American Standard Code for Information Interchange and is a character encoding standard for electronic communications. ASCII codes represent text in computers, telecommunications equipment, and other devices that use text.

Problem Statement

We have two strings of equal length. The goal is to perform the minimum exchange of characters at the same position in both strings so that the sum of the ASCII values ​​of the characters in each string is an odd number.

solution

• Calculate ASCII sum − Calculate the sum of ASCII values ​​for each string. Then, check if the sum is even or odd.

• Determine exchange requirements − If the sum is already odd, no exchange is required. If the sum is even, a swap is required.

• Find matching swaps − Find characters in two strings whose swapping would produce an odd sum. Track the number of exchanges.

• Return results− Return the minimum number of exchanges required.

Example

This is the modified code suitable for all scenarios -

#include <bits/stdc++.h>
using namespace std;

int minSwaps(string str1, string str2) {
   int len = str1.length();
   int ascii_sum1 = 0, ascii_sum2 = 0;
   
   for (int i = 0; i < len; i++) {
      ascii_sum1 += str1[i];
      ascii_sum2 += str2[i];
   }
   
   // If total sum is odd, it's impossible to have both sums odd
   if ((ascii_sum1 + ascii_sum2) % 2 != 0) return -1;
   
   // If both sums are odd already, no swaps are needed
   if (ascii_sum1 % 2 != 0 && ascii_sum2 % 2 != 0) return 0;
   
   // If both sums are even, we just need to make one of them odd
   if (ascii_sum1 % 2 == 0 && ascii_sum2 % 2 == 0) {
      for (int i = 0; i < len; i++) {
         // If we find an odd character in str1 and an even character in str2, or vice versa, swap them
         if ((str1[i] - '0') % 2 != (str2[i] - '0') % 2) return 1;
      }
   }

   // If we reach here, it means no eligible swaps were found
    return -1;
}

int main() {
   string str1 = "abc";
   string str2 = "def";
   
   int result = minSwaps(str1, str2);
   if(result == -1) {
      cout << "No valid swaps found.\n";
   } else {
      cout << "Minimum swaps required: " << result << endl;
   }
   
   return 0;
}

Output

No valid swaps found.

illustrate

Consider two strings -

str1 = "abc", str2 = "def"

We calculate the ASCII sum of str1 (294: a = 97, b = 98, c = 99) and str2 (303: d = 100, e = 101, f = 102). The ASCII sum is 597, which is an odd number. Therefore, it is impossible for both sums to be odd and the program will output "No valid swaps find".

The solution uses simple programming structures and logical reasoning to effectively solve the problem.

in conclusion

Minimizing swapping to obtain odd sums of ASCII values ​​is an interesting problem that enhances our understanding of string manipulation, character encoding, and problem-solving skills. The solutions provided use the C programming language and demonstrate how to handle different scenarios in the problem statement.

One thing to note is that this solution assumes that both strings are the same length. If you don't do this, you'll need additional logic to handle this situation.

The above is the detailed content of Minimize the number of swaps of characters with the same index so that the sum of the ASCII values ​​of the characters in the two strings is an odd number. For more information, please follow other related articles on the PHP Chinese website!