最小化相同索引字符的交换次数,以使两个字符串的ASCII值之和为奇数


在本文中,我们深入探讨了一个关于字符串操作和计算机科学中字符编码的引人入胜的问题。我们的任务是最小化两个字符串中相同索引字符之间的交换次数,以使两个字符串中字符的ASCII值之和为奇数。这是一种强大且通用的编程语言,深受许多软件开发人员的青睐。

了解ASCII

ASCII,即美国信息交换标准代码,是用于电子通信的字符编码标准。ASCII代码表示计算机、电信设备和其他使用文本的设备中的文本。

问题陈述

我们得到两个长度相等的字符串。目标是执行最少的相同位置字符交换,以便每个字符串中字符的ASCII值之和为奇数。

解决方案方法

  • 计算ASCII总和  计算每个字符串的ASCII值之和。然后,检查总和是偶数还是奇数。

  • 确定交换需求  如果总和已经是奇数,则不需要交换。如果总和是偶数,则需要交换。

  • 查找可交换项  查找两个字符串中交换后会产生奇数和的字符。跟踪交换次数。

  • 返回结果  返回所需的最少交换次数。

示例

以下是适用于所有场景的修改后的代码:

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

int minSwaps(char* str1, char* str2) {
   int len = strlen(str1);
   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 ((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() {
   char str1[] = "abc";
   char str2[] = "def";

   int result = minSwaps(str1, str2);
   if (result == -1) {
      printf("No valid swaps found.\n");
   } else {
      printf("Minimum swaps required: %d\n", result);
   }

   return 0;
}

输出

No valid swaps found.
#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 ((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;
}

输出

No valid swaps found.
public class Main {
   public static int minSwaps(String str1, String str2) {
      int len = str1.length();
      int asciiSum1 = 0, asciiSum2 = 0;

      for (int i = 0; i < len; i++) {
         asciiSum1 += str1.charAt(i);
         asciiSum2 += str2.charAt(i);
      }

      // If total sum is odd, it's impossible to have both sums odd
      if ((asciiSum1 + asciiSum2) % 2 != 0)
         return -1;

      // If both sums are odd already, no swaps are needed
      if (asciiSum1 % 2 != 0 && asciiSum2 % 2 != 0)
         return 0;

      // If both sums are even, we just need to make one of them odd
      if (asciiSum1 % 2 == 0 && asciiSum2 % 2 == 0) {
         for (int i = 0; i < len; i++) {
            if ((str1.charAt(i) - '0') % 2 != (str2.charAt(i) - '0') % 2)
               return 1;
         }
      }

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

   public static void main(String[] args) {
      String str1 = "abc";
      String str2 = "def";

      int result = minSwaps(str1, str2);
      if (result == -1) {
         System.out.println("No valid swaps found.");
      } else {
         System.out.println("Minimum swaps required: " + result);
      }
   }
}

输出

No valid swaps found.
def min_swaps(str1, str2):
   length = len(str1)
   ascii_sum1 = sum(ord(ch) for ch in str1)
   ascii_sum2 = sum(ord(ch) for ch in str2)

   # 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 and 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 and ascii_sum2 % 2 == 0:
      for i in range(length):
         if int(str1[i]) % 2 != int(str2[i]) % 2:
            return 1

   # If we reach here, it means no eligible swaps were found
   return -1

str1 = "abc"
str2 = "def"

result = min_swaps(str1, str2)
if result == -1:
   print("No valid swaps found.")
else:
   print("Minimum swaps required:", result)

输出

No valid swaps found.

解释

考虑两个字符串:

str1 = "abc", str2 = "def"

我们计算str1 (294: a = 97, b = 98, c = 99) 和str2 (303: d = 100, e = 101, f = 102) 的ASCII总和。ASCII总和为597,这是一个奇数。因此,不可能使两个总和都为奇数,程序将输出“未找到有效的交换”。

此解决方案使用简单的编程结构和逻辑推理有效地解决了问题。

结论

最小化交换次数以达到奇数ASCII值之和的任务是一个有趣的问题,它增强了我们对字符串操作、字符编码和问题解决能力的理解。提供的解决方案使用了各种编程语言,并演示了如何在问题陈述中处理不同的场景。

需要注意的是,此解决方案假设两个字符串具有相同的长度。如果长度不同,则需要额外的逻辑来处理这种情况。

更新于:2023年10月27日

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