Given a positive integer N, the task is to convert this integer to the maximum possible integer without leading zeroes by changing the digits. A digit X can only be changed into a digit Y if X + Y = 9.
Examples:
Input: N = 42
Output: 57
Change 4 -> 5 and 2 -> 7.
Input: N = 1
Output: 8
Approach: Only the digits which are greater than or equal to 5 need to be changed as changing the digits which are less than 5 will result in a larger number. After all the required digits have been updated, check whether the resultant number has a leading zero, if yes then change it to a 9.
Below is the implementation of the above approach:
// C++ implementation of the approach #include <bits/stdc++.h> using namespace std;
// Function to return the maximum possible // integer that can be obtained from the // given integer after performing // the given operations string maxInt(string str) { // For every digit
for ( int i = 0; i < str.length(); i++) {
// Digits greater than or equal to 5
// need not to be changed as changing
// them will lead to a smaller number
if (str[i] < '5' ) {
str[i] = ( '9' - str[i]) + '0' ;
}
}
// The resulting integer
// cannot have leading zero
if (str[0] == '0' )
str[0] = '9' ;
return str;
} // Driver code int main()
{ string str = "42" ;
cout << maxInt(str);
return 0;
} |
// Java implementation of the approach class GFG
{ // Function to return the maximum possible
// integer that can be obtained from the
// given integer after performing
// the given operations
static String maxInt( char str[])
{
// For every digit
for ( int i = 0 ; i < str.length; i++)
{
// Digits greater than or equal to 5
// need not to be changed as changing
// them will lead to a smaller number
if (str[i] < '5' )
{
str[i] = ( char )(( '9' - str[i]) + '0' );
}
}
// The resulting integer
// cannot have leading zero
if (str[ 0 ] == '0' )
str[ 0 ] = '9' ;
String str2 = new String(str);
return str2;
}
// Driver code
public static void main (String[] args)
{
String str = "42" ;
System.out.println(maxInt(str.toCharArray()));
}
} // This code is contributed by AnkitRai01 |
# Python3 implementation of the approach # Function to return the maximum possible # integer that can be obtained from the # given integer after performing # the given operations def maxInt(string):
string2 = ""
# For every digit
for i in range ( 0 , len (string)):
# Digits greater than or equal to 5
# need not to be changed as changing
# them will lead to a smaller number
if (string[i] < '5' ):
string2 + = str (( ord ( '9' ) - ord (string[i])))
else :
string2 + = str (string[i])
# The resulting integer
# cannot have leading zero
if (string2[ 0 ] = = '0' ):
string2[ 0 ] = '9'
return string2
# Driver code if __name__ = = '__main__' :
string = "42"
print (maxInt(string))
# This code is contributed by ashutosh450 |
// C# implementation of the approach using System;
class GFG
{ // Function to return the maximum possible
// integer that can be obtained from the
// given integer after performing
// the given operations
static String maxInt( char []str)
{
// For every digit
for ( int i = 0; i < str.Length; i++)
{
// Digits greater than or equal to 5
// need not to be changed as changing
// them will lead to a smaller number
if (str[i] < '5' )
{
str[i] = ( char )(( '9' - str[i]) + '0' );
}
}
// The resulting integer
// cannot have leading zero
if (str[0] == '0' )
str[0] = '9' ;
String str2 = new String(str);
return str2;
}
// Driver code
public static void Main (String []args)
{
String str = "42" ;
Console.WriteLine(maxInt(str.ToCharArray()));
}
} // This code is contributed by Arnab Kundu |
<script> // Javascript implementation of the // above approach // Function to return the maximum possible // integer that can be obtained from the // given integer after performing // the given operations function maxInt(str)
{ // For every digit
var str2 = "" ;
for ( var i = 0; i < str.length; i++) {
// Digits greater than or equal to 5
// need not to be changed as changing
// them will lead to a smaller number
if (str[i] < '5' ) {
var l = ( '9' .charCodeAt(0) - str[i].charCodeAt(0)) + '0' .charCodeAt(0);
str2 = str2.concat(String.fromCharCode(l));
}
}
// The resulting integer
// cannot have leading zero
if (str2[0] == '0' )
str2[0] = '9' ;
return str2;
} // Driver code var str = "42" ;
document.write(maxInt(str)) // This code is contributed by ShubhamSingh10 </script> |
57
Time Complexity: O(|str|)
Auxiliary Space: O(1)