Given a string Time Format, the task is to check whether the string follows the time formats “HH: MM: SS” or “HH: MM” using Regular Expression. Rules for valid time formats:
- It should contain only digits[0-9] and colon (:).
- No alphabets are allowed or any special characters.
Examples:
Input: “12: 55”
Output: TrueInput: “24: 12: 12”
Output: False
Explanation: The standard time is never expressed 24:00:00 hours or anything else after that.
Approach: The problem can be solved based on the following idea:
Create a regex pattern to validate the number as written below:
regex= “^(?:[01]?[0-9]|2[0-3]):[0-5]?[0-9](?::[0-5]?[0-9])?$“^ : Beginning of the string
?: : not compulsion to be present
[01] : indicates either 1 or 0
[0 – 9] : any one digit from 0 to 9 should be present.
\ : either first part before ” or second part after ”.
Follow the below steps to implement the idea:
- Create regex expression for Time formats.
- Use Pattern class to compile the regex formed.
- Use the matcher function to check whether the Time format is valid or not.
- If it is valid, return true. Otherwise, return false.
Below is the implementation of the above approach.
C++
// C++ program to validate the// Traditional Time Formats (HH:MM:SS or HH:MM)// using RegularExpression#include <bits/stdc++.h>#include <regex>using namespace std;// Function to validate the// Traditional Time Formats (HH:MM:SS or HH:MM)string isValidTime(string str){ // Regex to check valid // Traditional Time Formats // (HH:MM:SS or HH:MM). const regex pattern("^(?:[01]?[0-9]|2[0-3]):[0-5]?[0-9]" "(?::[0-5]?[0-9])?$"); // If the str // is empty return false if (str.empty()) { return "false"; } // Return true if the str // matched the ReGex if (regex_match(str, pattern)) { return "true"; } else { return "false"; }}// Driver Codeint main(){ // Test Case 1: string str1 = "23:01:00"; cout << isValidTime(str1) << endl; // Test Case 2: string str2 = "12:59:00"; cout << isValidTime(str2) << endl; // Test Case 3: string str3 = "19:00:59"; cout << isValidTime(str3) << endl; // Test Case 4: string str4 = "19:00:96"; cout << isValidTime(str4) << endl; // Test Case 5: string str5 = "08:78:70"; cout << isValidTime(str5) << endl; // Test Case 6: string str6 = "00:98:00"; cout << isValidTime(str6) << endl; return 0;} |
Java
// Java code to implement the approachimport java.util.regex.*;class GFG { // Function to validate the // Traditional Time Formats // (HH:MM:SS or HH:MM) public static boolean isValidTime(String str) { // Regex to check valid Time String regex = "^(?:[01]?[0-9]|2[0-3]):[0-5]?[0-9](?::[0-5]?[0-9])?$"; // Compile the ReGex Pattern p = Pattern.compile(regex); // If the str // is empty return false if (str == null) { return false; } // Pattern class contains matcher() // method to find matching between // given str using regex. Matcher m = p.matcher(str); // Return if the str // matched the ReGex return m.matches(); } // Driver Code. public static void main(String args[]) { // Test Case 1: String str1 = "23:10:59"; System.out.println(isValidTime(str1)); // Test Case 2: String str2 = "12:59:00"; System.out.println(isValidTime(str2)); // Test Case 3: String str3 = "19:00:59"; System.out.println(isValidTime(str3)); // Test Case 4: String str4 = "19:00:96"; System.out.println(isValidTime(str4)); // Test Case 5: String str5 = "08:78:70"; System.out.println(isValidTime(str5)); // Test Case 6: String str6 = "00:98:00"; System.out.println(isValidTime(str6)); }} |
Python3
# Python3 program to validate# Traditional Time Formats (HH:MM:SS or HH:MM) # using Regular Expressionimport re# Function to validate# Traditional Time Formats (HH:MM:SS or HH:MM)def isValidTime(str): # Regex to check valid time regex = "^(?:[01]?[0-9]|2[0-3]):[0-5]?[0-9](?::[0-5]?[0-9])?$" # Compile the ReGex p = re.compile(regex) # If the string is empty # return false if (str == None): return "false" # Return if the string # matched the ReGex if(re.search(p, str)): return "true" else: return "false"# Driver codeif __name__ == '__main__': # Test Case 1: str1 = "23:01:00" print(isValidTime(str1)) # Test Case 2: str2 = "12:59:00" print(isValidTime(str2)) # Test Case 3: str3 = "19:00:59" print(isValidTime(str3)) # Test Case 4: str4 = "19:00:96" print(isValidTime(str4)) # Test Case 5: str5 = "08:78:70" print(isValidTime(str5)) # Test Case 6: str6 = "00:98:00" print(isValidTime(str6)) |
C#
// Include namespace systemusing System;using System.Text.RegularExpressions;public class GFG{ // Function to validate the // Traditional Time Formats // (HH:MM:SS or HH:MM) public static bool isValidTime(String str) { // Regex to check valid LEI Code var regex = new Regex("^(?:[01]?[0-9]|2[0-3]):[0-5]?[0-9](?::[0-5]?[0-9])?$"); // If the str // is empty return false if (str == null) { return false; } // Pattern class contains matcher() // method to find matching between // given LEI Code using regex. var m = regex.Match(str); // Return if the MICR Code // matched the ReGex return m.Success; } // Driver Code. public static void Main(String[] args) { // Test Case 1: var str1 = "23:10:59"; Console.WriteLine(GFG.isValidTime(str1)); // Test Case 2: var str2 = "12:59:00"; Console.WriteLine(GFG.isValidTime(str2)); // Test Case 3: var str3 = "19:00:59"; Console.WriteLine(GFG.isValidTime(str3)); // Test Case 4: var str4 = "19:00:96"; Console.WriteLine(GFG.isValidTime(str4)); // Test Case 5: var str5 = "08:78:70"; Console.WriteLine(GFG.isValidTime(str5)); // Test Case 6: var str6 = "00:98:00"; Console.WriteLine(GFG.isValidTime(str6)); }}// This code is contributed by Potta Lokesh. |
Javascript
// Javascript program to validate// Traditional Time Formats (HH:MM:SS or HH:MM)//using Regular Expression// Function to validate the// Traditional Time Formats (HH:MM:SS or HH:MM)function isValidTime(str) { // Regex to check valid // Traditional Time Formats (HH:MM:SS or HH:MM) let regex = new RegExp(/^(?:[01]?[0-9]|2[0-3]):[0-5]?[0-9](?::[0-5]?[0-9])?$/); // if str // is empty return false if (str == null) { return "false"; } // Return true if the str // matched the ReGex if (regex.test(str) == true) { return "true"; } else { return "false"; }}// Driver Code// Test Case 1:let str1 = "23:01:00";console.log(isValidTime(str1));// Test Case 2:let str2 = "12:59:00";console.log(isValidTime(str2));// Test Case 3:let str3 = "19:00:59";console.log(isValidTime(str3));// Test Case 4:let str4 = "19:00:96";console.log(isValidTime(str4));// Test Case 5:let str5 = "08:78:70";console.log(isValidTime(str5));// Test Case 6:let str6 = "00:98:00";console.log(isValidTime(str6)); |
Output
true true true false false false
Time Complexity: O(N) for each testcase, where N is the length of the given string.
Auxiliary Space: O(1)
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