查找最长子字符串,其中没有相邻的英文字母
在字符串操作领域,识别模式和提取有意义的子字符串是常见任务。一个有趣的问题涉及查找最长的子字符串,其中没有相邻的字符是相邻的英文字母。在本文中,我们将深入探讨解决此问题的有效解决方案,并提供清晰的解释和示例测试用例。
问题陈述
给定一个由小写英文字母组成的字符串,我们需要找到最长子字符串的长度,其中没有相邻的字符是相邻的英文字母。例如,在字符串“abacabx”中,满足此条件的最长子字符串是“abx”,长度为3。
方法和算法
为了解决这个问题,我们可以利用贪心算法。我们将遍历给定的字符串,并检查当前字符和前一个字符是否为相邻的英文字母。如果是,我们将开始一个新的子字符串。否则,我们将扩展现有的子字符串。通过在最长子字符串的长度超过之前最大值时更新它,我们可以找到所需的结果。
实现
以下是解决问题的代码:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
// Function to find the longest substring with consecutive characters having a difference of 1 in their ASCII values
int findLongestSubstring(const char* str) {
int maxLength = 0;
int currentLength = 1;
// Loop through the characters in the string
for (int i = 1; i < strlen(str); i++) {
// Check if the difference between adjacent characters is not equal to 1
if (abs(str[i] - str[i - 1]) != 1) {
currentLength++; // Increment the current substring length
} else {
maxLength = (maxLength > currentLength) ? maxLength : currentLength; // Update the maximum length if needed
currentLength = 1; // Reset the current substring length
}
}
maxLength = (maxLength > currentLength) ? maxLength : currentLength; // Check for the last substring
return maxLength; // Return the length of the longest substring
}
int main() {
const char* inputString = "abacabx";
int longestSubstringLength = findLongestSubstring(inputString);
printf("Longest substring length: %d\n", longestSubstringLength);
return 0;
}
输出
Longest substring length: 3
#include <iostream>
#include <string>
using namespace std;
int findLongestSubstring(const string& str) {
int maxLength = 0;
int currentLength = 1;
for (int i = 1; i < str.length(); i++) {
if (abs(str[i] - str[i - 1]) != 1) {
currentLength++;
} else {
maxLength = max(maxLength, currentLength);
currentLength = 1;
}
}
maxLength = max(maxLength, currentLength);
return maxLength;
}
int main() {
string inputString = "abacabx";
int longestSubstringLength = findLongestSubstring(inputString);
cout << "Longest substring length: " << longestSubstringLength << endl;
return 0;
}
输出
Longest substring length: 3
public class LongestSubstring {
public static int findLongestSubstring(String str) {
int maxLength = 0;
int currentLength = 1;
// Loop through the characters in the string
for (int i = 1; i < str.length(); i++) {
// Check if the difference between adjacent characters is not equal to 1
if (Math.abs(str.charAt(i) - str.charAt(i - 1)) != 1) {
currentLength++; // Increment the current substring length
} else {
maxLength = Math.max(maxLength, currentLength); // Update the maximum length if needed
currentLength = 1; // Reset the current substring length
}
}
maxLength = Math.max(maxLength, currentLength); // Check for the last substring
return maxLength; // Return the length of the longest substring
}
public static void main(String[] args) {
String inputString = "abacabx";
int longestSubstringLength = findLongestSubstring(inputString);
System.out.println("Longest substring length: " + longestSubstringLength);
}
}
输出
Longest substring length: 3
def find_longest_substring(s):
max_length = 0
current_length = 1
# Loop through the characters in the string
for i in range(1, len(s)):
# Check if the difference between adjacent characters is not equal to 1
if abs(ord(s[i]) - ord(s[i - 1])) != 1:
current_length += 1 # Increment the current substring length
else:
max_length = max(max_length, current_length) # Update the maximum length if needed
current_length = 1 # Reset the current substring length
max_length = max(max_length, current_length) # Check for the last substring
return max_length # Return the length of the longest substring
def main():
input_string = "abacabx"
longest_substring_length = find_longest_substring(input_string)
print("Longest substring length:", longest_substring_length)
if __name__ == "__main__":
main()
输出
Longest substring length: 3
代码解释
函数 findLongestSubstring 将输入字符串作为参数,并返回没有相邻的英文字母字符的最长子字符串的长度。
我们分别将 maxLength 和 currentLength 初始化为 0 和 1。然后,我们从第二个字符开始遍历字符串。如果当前字符和前一个字符之间的绝对差值不等于 1,我们将增加 currentLength 以扩展当前子字符串。否则,如果当前长度超过之前最大值,我们将更新 maxLength 并将 currentLength 重置为 1。
最后,我们返回找到的最大长度。在主函数中,我们提供了一个示例输入字符串“abacabx”并打印最长子字符串的长度。
示例测试用例
让我们考虑示例字符串“abacabx”来演示我们的解决方案。
string inputString = "abacabx";
在这种情况下,没有相邻的英文字母字符的最长子字符串是“abx”,长度为3。
结论
通过采用简单有效的方法,我们成功地解决了使用 C++ 查找没有相邻的英文字母字符的最长子字符串的问题。了解提供的代码和解释将使您能够解决涉及字符串操作的类似问题。
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