Given three positive integers X, Y, and B, where X and Y are Base-B integers, the task is to find the value of X – Y such that X >= Y.
Examples:
Input: X = 1212, Y = 256, B = 8
Output: 0734
Explanation: The value of 1212 – 256 in base 8 is 734.Input: X = 546, Y = 248, B = 9
Output: 287
Approach: The given problem can be solved by using basic mathematics subtraction. Follow the steps below to solve the given problem:
- Initialize two variables say power = 1, carry = 0, to keep track of current power and carry generated while subtracting respectively.
- Initialize a variable, say finalVal = 0, to store the resultant value of X – Y.
- Iterate a loop until X > 0 and perform the following steps:
- Store last digits from the current value of X and Y in two variables, say n1 = X % 10 and n2 = Y % 10 respectively.
- Remove last digits from X and Y by updating X = X / 10 and Y = Y / 10.
- Initialize temp = n1 – n2 + carry.
- If temp < 0, then add base B to N, that is N = N + B and set carry = -1, which will act as a borrow. Otherwise, set carry = 0.
- Add current temp * power to finalVal, that is finalVal = finalVal + temp * power and set power = power * 10.
- After completing the above steps, print the value of finalVal as the result.
Below is the implementation of the above approach:
C++
// C++ program for the above approach #include <bits/stdc++.h> using namespace std; // Function to find X - Y in base B int getDifference( int B, int X, int Y) { // To store final answer int finalVal = 0; // To store carry generated int carry = 0; // To keep track of power int power = 1; while (X > 0) { // Store last digits of current // value of X and Y in n1 and // n2 respectively int n1 = X % 10; int n2 = Y % 10; // Remove last digits from // X and Y X = X / 10; Y = Y / 10; int temp = n1 - n2 + carry; if (temp < 0) { // Carry = -1 will act // as borrow carry = -1; temp += B; } else { carry = 0; } // Add in final result finalVal += temp * power; power = power * 10; } // Return final result return finalVal; } // Driver Code int main() { int X = 1212; int Y = 256; int B = 8; cout << (getDifference(B, X, Y)); return 0; } // This code is contributed by rakeshsahni |
Java
// Java program for the above approach import java.io.*; class GFG { // Function to find X - Y in base B public static int getDifference( int B, int X, int Y) { // To store final answer int finalVal = 0 ; // To store carry generated int carry = 0 ; // To keep track of power int power = 1 ; while (X > 0 ) { // Store last digits of current // value of X and Y in n1 and // n2 respectively int n1 = X % 10 ; int n2 = Y % 10 ; // Remove last digits from // X and Y X = X / 10 ; Y = Y / 10 ; int temp = n1 - n2 + carry; if (temp < 0 ) { // Carry = -1 will act // as borrow carry = - 1 ; temp += B; } else { carry = 0 ; } // Add in final result finalVal += temp * power; power = power * 10 ; } // Return final result return finalVal; } // Driver Code public static void main(String[] args) { int X = 1212 ; int Y = 256 ; int B = 8 ; System.out.println( getDifference(B, X, Y)); } } |
Python3
# Python3 program for the above approach # Function to find X - Y in base B def getDifference(B, X, Y) : # To store final answer finalVal = 0 ; # To store carry generated carry = 0 ; # To keep track of power power = 1 ; while (X > 0 ) : # Store last digits of current # value of X and Y in n1 and # n2 respectively n1 = X % 10 ; n2 = Y % 10 ; # Remove last digits from # X and Y X = X / / 10 ; Y = Y / / 10 ; temp = n1 - n2 + carry; if (temp < 0 ) : # Carry = -1 will act # as borrow carry = - 1 ; temp + = B; else : carry = 0 ; # Add in final result finalVal + = temp * power; power = power * 10 ; # Return final result return finalVal; # Driver Code if __name__ = = "__main__" : X = 1212 ; Y = 256 ; B = 8 ; print (getDifference(B, X, Y)); # This code is contributed by AnkThon |
C#
// C# program for the above approach using System; public class GFG { // Function to find X - Y in base B public static int getDifference( int B, int X, int Y) { // To store final answer int finalVal = 0; // To store carry generated int carry = 0; // To keep track of power int power = 1; while (X > 0) { // Store last digits of current // value of X and Y in n1 and // n2 respectively int n1 = X % 10; int n2 = Y % 10; // Remove last digits from // X and Y X = X / 10; Y = Y / 10; int temp = n1 - n2 + carry; if (temp < 0) { // Carry = -1 will act // as borrow carry = -1; temp += B; } else { carry = 0; } // Add in final result finalVal += temp * power; power = power * 10; } // Return final result return finalVal; } // Driver Code public static void Main( string [] args) { int X = 1212; int Y = 256; int B = 8; Console.WriteLine(getDifference(B, X, Y)); } } // This code is contributed by AnkThon |
Javascript
<script> // Javascript program for the above approach // Function to find X - Y in base B function getDifference(B, X, Y) { // To store final answer let finalVal = 0; // To store carry generated let carry = 0; // To keep track of power let power = 1; while (X > 0) { // Store last digits of current // value of X and Y in n1 and // n2 respectively let n1 = X % 10; let n2 = Y % 10; // Remove last digits from // X and Y X = Math.floor(X / 10); Y = Math.floor(Y / 10); let temp = n1 - n2 + carry; if (temp < 0) { // Carry = -1 will act // as borrow carry = -1; temp += B; } else { carry = 0; } // Add in final result finalVal += temp * power; power = power * 10; } // Return final result return finalVal; } // Driver Code let X = 1212; let Y = 256; let B = 8; document.write(getDifference(B, X, Y)); // This code is contributed by gfgking </script> |
734
Time Complexity: O(log10N)
Auxiliary Space: O(1)
However, we can optimize the solution by performing the following steps:
- First, convert the given numbers X and Y into decimal form.
- Then, find the difference between X and Y.
- Finally, convert the decimal difference back into the given base.
Here’s the implementation of the above approach:
C++
//C++ progarm for above approach #include <iostream> #include <cmath> using namespace std; // Function to convert a number in given base // to decimal form int toDecimal( int num, int base) { int res = 0, power = 1; while (num > 0) { int digit = num % 10; res += digit * power; power *= base; num /= 10; } return res; } // Function to convert a decimal number // to given base form int toBase( int num, int base) { int res = 0, power = 1; while (num > 0) { int digit = num % base; res += digit * power; power *= 10; num /= base; } return res; } // Function to find X - Y in base B int getDifference( int B, int X, int Y) { // Convert X and Y to decimal form int X_dec = toDecimal(X, B); int Y_dec = toDecimal(Y, B); // Find the difference in decimal form int diff_dec = X_dec - Y_dec; // Convert the difference to base B form int diff = toBase(diff_dec, B); // Return the difference return diff; } // Driver Code int main() { int X = 1212; int Y = 256; int B = 8; cout << getDifference(B, X, Y); return 0; } |
Java
//Java code for above approach import java.lang.Math; public class Main { // Function to convert a number in given base // to decimal form static int toDecimal( int num, int base) { int res = 0 , power = 1 ; while (num > 0 ) { int digit = num % 10 ; res += digit * power; power *= base; num /= 10 ; } return res; } // Function to convert a decimal number // to given base form static int toBase( int num, int base) { int res = 0 , power = 1 ; while (num > 0 ) { int digit = num % base; res += digit * power; power *= 10 ; num /= base; } return res; } // Function to find X - Y in base B static int getDifference( int B, int X, int Y) { // Convert X and Y to decimal form int X_dec = toDecimal(X, B); int Y_dec = toDecimal(Y, B); // Find the difference in decimal form int diff_dec = X_dec - Y_dec; // Convert the difference to base B form int diff = toBase(diff_dec, B); // Return the difference return diff; } // Driver Code public static void main(String[] args) { int X = 1212 ; int Y = 256 ; int B = 8 ; System.out.println(getDifference(B, X, Y)); } } |
Output:
734
Time Complexity: O(log^2 N)
Auxiliary Space: O(log N)
Ready to dive in? Explore our Free Demo Content and join our DSA course, trusted by over 100,000 neveropen!