Given a string S representing a time in 24 hours format, with ‘_’ placed at positions of some digits, the task is to find the maximum time possible by replacing the characters ‘_’ with any digit.
Examples:
Input: S = “0_:4_”
Output: 09:39
Explanation: Replacing the characters S[1] and S[4] with ‘9’ modifies the string to “09:49”, which is the maximum time possible.Input: S = “__:__”
Output: 23:59
Approach: The given problem can be solved by greedily selecting the digits for each ‘_’ present in the string. Follow the steps below to solve the problem:
- If the character S[0] is equal to ‘_’ and S[1] is either ‘_’ or is less than 4, then assign ‘2‘ to S[0]. Otherwise, assign ‘1’ to S[0].
- If the character S[1] is equal to ‘_’ and S[0] is ‘2’, then assign ‘3’ to S[1]. Otherwise, assign ‘9‘ to S[1].
- If the character S[3] is equal to ‘_’, then assign ‘5’ to S[3].
- If the character S[4] is equal to ‘_’, then assign ‘9‘ to S[4].
- After completing the above steps, print the modified string S.
Below is the implementation of the above approach:
// C++ program for the above approach #include <bits/stdc++.h> using namespace std;
// Function to find the maximum // time possible by replacing // each '_' with any digit string maximumTime(string s) { // If the first character is '_'
if (s[0] == '_' ) {
// If s[1] is '_' or
// s[1] is less than 4
if ((s[1] == '_' )
|| (s[1] >= '0'
&& s[1] < '4' )) {
// Update s[0] as 2
s[0] = '2' ;
}
// Otherwise, update s[0] = 1
else {
s[0] = '1' ;
}
}
// If s[1] is equal to '_'
if (s[1] == '_' ) {
// If s[0] is equal to '2'
if (s[0] == '2' ) {
s[1] = '3' ;
}
// Otherwise
else {
s[1] = '9' ;
}
}
// If S[3] is equal to '_'
if (s[3] == '_' ) {
s[3] = '5' ;
}
// If s[4] is equal to '_'
if (s[4] == '_' ) {
s[4] = '9' ;
}
// Return the modified string
return s;
} // Driver Code int main()
{ string S = "0_:4_" ;
cout << maximumTime(S);
return 0;
} |
// Java program for the above approach class GFG{
// Function to find the maximum // time possible by replacing // each '_' with any digit static void maximumTime(String str)
{ char []s = str.toCharArray();
// If the first character is '_'
if (s[ 0 ] == '_' )
{
// If s[1] is '_' or
// s[1] is less than 4
if ((s[ 1 ] == '_' ) ||
(s[ 1 ] >= '0' && s[ 1 ] < '4' ))
{
// Update s[0] as 2
s[ 0 ] = '2' ;
}
// Otherwise, update s[0] = 1
else
{
s[ 0 ] = '1' ;
}
}
// If s[1] is equal to '_'
if (s[ 1 ] == '_' )
{
// If s[0] is equal to '2'
if (s[ 0 ] == '2' )
{
s[ 1 ] = '3' ;
}
// Otherwise
else
{
s[ 1 ] = '9' ;
}
}
// If S[3] is equal to '_'
if (s[ 3 ] == '_' )
{
s[ 3 ] = '5' ;
}
// If s[4] is equal to '_'
if (s[ 4 ] == '_' )
{
s[ 4 ] = '9' ;
}
// Print the modified string
for ( int i = 0 ; i < s.length; i++)
System.out.print(s[i]);
} // Driver Code static public void main (String []args)
{ String S = "0_:4_" ;
maximumTime(S);
} } // This code is contributed by AnkThon |
# Python3 program for the above approach # Function to find the maximum # time possible by replacing # each '_' with any digit def maximumTime(s):
s = list (s)
# If the first character is '_'
if (s[ 0 ] = = '_' ):
# If s[1] is '_' or
# s[1] is less than 4
if ((s[ 1 ] = = '_' ) or (s[ 1 ] > = '0' and
s[ 1 ] < '4' )):
# Update s[0] as 2
s[ 0 ] = '2'
# Otherwise, update s[0] = 1
else :
s[ 0 ] = '1'
# If s[1] is equal to '_'
if (s[ 1 ] = = '_' ):
# If s[0] is equal to '2'
if (s[ 0 ] = = '2' ):
s[ 1 ] = '3'
# Otherwise
else :
s[ 1 ] = '9'
# If S[3] is equal to '_'
if (s[ 3 ] = = '_' ):
s[ 3 ] = '5'
# If s[4] is equal to '_'
if (s[ 4 ] = = '_' ):
s[ 4 ] = '9'
# Return the modified string
s = ''.join(s)
return s
# Driver Code if __name__ = = '__main__' :
S = "0_:4_"
print (maximumTime(S))
# This code is contributed by ipg2016107 |
// C# program for the above approach using System;
class GFG{
// Function to find the maximum // time possible by replacing // each '_' with any digit static void maximumTime( string str)
{ char []s = str.ToCharArray();
// If the first character is '_'
if (s[0] == '_' )
{
// If s[1] is '_' or
// s[1] is less than 4
if ((s[1] == '_' ) ||
(s[1] >= '0' && s[1] < '4' ))
{
// Update s[0] as 2
s[0] = '2' ;
}
// Otherwise, update s[0] = 1
else
{
s[0] = '1' ;
}
}
// If s[1] is equal to '_'
if (s[1] == '_' )
{
// If s[0] is equal to '2'
if (s[0] == '2' )
{
s[1] = '3' ;
}
// Otherwise
else
{
s[1] = '9' ;
}
}
// If S[3] is equal to '_'
if (s[3] == '_' )
{
s[3] = '5' ;
}
// If s[4] is equal to '_'
if (s[4] == '_' )
{
s[4] = '9' ;
}
// Print the modified string
for ( int i = 0; i < s.Length; i++)
Console.Write(s[i]);
} // Driver Code static public void Main ()
{ string S = "0_:4_" ;
maximumTime(S);
} } // This code is contributed by AnkThon |
<script> // javascript program for the above approach // Function to find the maximum // time possible by replacing // each '_' with any digit function maximumTime(str)
{ var s = str.split( "" );
// If the first character is '_'
if (s[0] == '_' )
{
// If s[1] is '_' or
// s[1] is less than 4
if ((s[1] == '_' ) ||
(s[1] >= '0' && s[1] < '4' ))
{
// Update s[0] as 2
s[0] = '2' ;
}
// Otherwise, update s[0] = 1
else
{
s[0] = '1' ;
}
}
// If s[1] is equal to '_'
if (s[1] == '_' )
{
// If s[0] is equal to '2'
if (s[0] == '2' )
{
s[1] = '3' ;
}
// Otherwise
else
{
s[1] = '9' ;
}
}
// If S[3] is equal to '_'
if (s[3] == '_' )
{
s[3] = '5' ;
}
// If s[4] is equal to '_'
if (s[4] == '_' )
{
s[4] = '9' ;
}
// Print the modified string
for ( var i = 0; i < s.length; i++)
document.write(s[i]);
} // Driver Code var S = "0_:4_" ;
maximumTime(S);
// This code is contributed by bunnyram19. </script> |
// C program for above approach #include <stdio.h> #include <string.h> // Function to find the maximum // time possible by replacing // each '_' with any digit char * maximumTime( char s[])
{ // If the first character is '_'
if (s[0] == '_' ) {
// If s[1] is '_' or
// s[1] is less than 4
if ((s[1] == '_' ) || (s[1] >= '0' && s[1] < '4' )) {
// Update s[0] as 2
s[0] = '2' ;
}
else { // Otherwise, update s[0] = 1
s[0] = '1' ;
}
}
// If s[1] is equal to '_'
if (s[1] == '_' ) {
// If s[0] is equal to '2'
if (s[0] == '2' ) {
s[1] = '3' ;
}
// otherwise
else {
s[1] = '9' ;
}
}
// If S[3] is equal to '_'
if (s[3] == '_' ) {
s[3] = '5' ;
}
// If s[4] is equal to '_'
if (s[4] == '_' ) {
s[4] = '9' ;
}
return s; // Return the modified string
} int main()
{ char S[] = "0_:4_" ;
printf ( "%s" , maximumTime(S));
return 0;
} // This code is contributed by Tapesh (tapeshdua420) |
09:49
Time Complexity: O(1)
Auxiliary Space: O(1)