Check if a number can be expressed as a^b in Python


Suppose we have a number n. We have to check whether we can make express it like a^b or not.

So, if the input is like 125, then the output will be True as 125 = 5^3, so a = 5 and b = 3

To solve this, we will follow these steps −

  • if num is same as 1, then:
    • return true
  • for initialize i := 2, when i * i <= num, update (increase i by 1), do:
    • val := log(num) / log(i)
    • if val - integer part of val is nearly 0, then:
      • return true
  • return false

Let us see the following implementation to get better understanding −

Example

Live Demo

#include<iostream> #include<cmath> using namespace std; bool solve(int num) {    if (num == 1)       return true;      for (int i = 2; i * i <= num; i++) {       double val = log(num) / log(i);       if ((val - (int)val) < 0.00000001)          return true;    }        return false; }   int main() {    int n = 125;    cout << solve(n); }

Input

125

Output

1

Updated on: 16-Jan-2021

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