查詢最長子字串,其中沒有相鄰的英文字母
在字串操作領域,識別模式和提取有意義的子字串是常見任務。一個有趣的問題涉及查詢最長的子字串,其中沒有相鄰的字元是相鄰的英文字母。在本文中,我們將深入探討解決此問題的有效解決方案,並提供清晰的解釋和示例測試用例。
問題陳述
給定一個由小寫英文字母組成的字串,我們需要找到最長子字串的長度,其中沒有相鄰的字元是相鄰的英文字母。例如,在字串“abacabx”中,滿足此條件的最長子字串是“abx”,長度為3。
方法和演算法
為了解決這個問題,我們可以利用貪心演算法。我們將遍歷給定的字串,並檢查當前字元和前一個字元是否為相鄰的英文字母。如果是,我們將開始一個新的子字串。否則,我們將擴充套件現有的子字串。透過在最長子字串的長度超過之前最大值時更新它,我們可以找到所需的結果。
實現
以下是解決問題的程式碼:
#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; }
輸出
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; }
輸出
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); } }
輸出
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()
輸出
Longest substring length: 3
程式碼解釋
函式 findLongestSubstring 將輸入字串作為引數,並返回沒有相鄰的英文字母字元的最長子字串的長度。
我們分別將 maxLength 和 currentLength 初始化為 0 和 1。然後,我們從第二個字元開始遍歷字串。如果當前字元和前一個字元之間的絕對差值不等於 1,我們將增加 currentLength 以擴充套件當前子字串。否則,如果當前長度超過之前最大值,我們將更新 maxLength 並將 currentLength 重置為 1。
最後,我們返回找到的最大長度。在主函式中,我們提供了一個示例輸入字串“abacabx”並列印最長子字串的長度。
示例測試用例
讓我們考慮示例字串“abacabx”來演示我們的解決方案。
string inputString = "abacabx";
在這種情況下,沒有相鄰的英文字母字元的最長子字串是“abx”,長度為3。
結論
透過採用簡單有效的方法,我們成功地解決了使用 C++ 查詢沒有相鄰的英文字母字元的最長子字串的問題。瞭解提供的程式碼和解釋將使您能夠解決涉及字串操作的類似問題。