透過交換相鄰字串中的字元，使所有字串都成為迴文串

#include <stdio.h>
#include <string.h>

// Function to get character from the ind index of all strings
void getColumnChars(char arr[][100], int rows, int ind, char chars[]) {
   for (int i = 0; i < rows; i++) {
      chars[i] = arr[i][ind];
   }
}

// Function to check if it's possible to swap and make both lists the same
int isSwapPossible(char temp1[], char temp2[], int rows) {
   int freq[256] = {0};
   // Store frequency of characters of temp1
   for (int i = 0; i < rows; i++) {
      freq[temp1[i]]++;
   }
   // Subtract frequency of characters of temp2
   for (int i = 0; i < rows; i++) {
      freq[temp2[i]]--;
   }
   for (int i = 0; i < 256; i++) {
      // When characters are not the same in both rows, return 0.
      if (freq[i] != 0) {
         return 0;
      }
   }
   return 1;
}

// Function to count swaps required to make both lists the same
int countSwaps(char temp1[], char temp2[], int rows) {
   int sps = 0;
   int p = 0;
   while (p != rows) {
      if (temp1[p] != temp2[p]) {
         if (p == rows - 1) {
            // For the last character
            char temp = temp2[p - 1];
            temp2[p - 1] = temp2[p];
            temp2[p] = temp;
         } else {
            // For other characters
            char temp = temp2[p];
            temp2[p] = temp2[p + 1];
            temp2[p + 1] = temp;
         }
         // Increment number of swaps
         sps += 1;
         p = 0;
      } else {
         p += 1;
      }
   }
   return sps;
}

int numberOfSwaps(char arr[][100], int rows, int cols) {
   int cnt = 0;
   int str_len = cols;
   for (int p = 0; p < str_len / 2; p++) {
      char temp1[100];
      char temp2[100];
      getColumnChars(arr, rows, p, temp1);
      getColumnChars(arr, rows, str_len - p - 1, temp2);
      // When each string contains the same character at p and str_len - p - 1 index
      if (memcmp(temp1, temp2, rows) == 0) {
         continue;
      }
      // Check whether possible to make temp1 and temp2 equal by swapping characters
      if (!isSwapPossible(temp1, temp2, rows)) {
         cnt = -1;
         break;
      } else {
         cnt += countSwaps(temp1, temp2, rows);
      }
   }
   return cnt;
}

int main() {
   char arr[][100] = {"57", "65", "76"};
   int rows = 3;
   int cols = 2;
   int result = numberOfSwaps(arr, rows, cols);
   printf("The minimum number of swaps required to make all strings palindromic is %d\n", result);
   return 0;
}

輸出

The minimum number of swaps required to make all strings palindromic is 2