/* Kaprekar Number: A Kaprekar Number is a positive integer that, after being squared and split into two lexicographical parts, is equal to the sum of the two new numbers obtained: If the quantity of digits of the squared number is even, the left and right parts will have the same length. For Example : square number of 5 is 25 is even means it contains 2 digits so left part will be 2 and right part will be 5. If the quantity of digits of the squared number is odd, then the right part will be the longest half, with the left part being the smallest or equal to zero if the quantity of digits is equal to 1. For Example 1 : square number of 25 is 625 is odd means it contains 3 digits so left part will be 6 and right part will be 25. For Example 2 : square number of 3 is 9 is odd means it contains 1 digits so left part will be 0 and right part will be 9. Note :- Given a positive integer n implement a function that returns true if it's a Kaprekar number, and false if it's not. Example: Input :- 3 n² = "9" Left + Right = 0 + 9 = 9 ➞ 9 !== 3 Output :- false Input :- 5 n² = "25" Left + Right = 2 + 5 = 7 ➞ 7 !== 5 Output :- false Input :- 297 n² = "88209" Left + Right = 88 + 209 = 297 ➞ 297 === 297 Output :- true Challenge Link -> https://code.sololearn.com/WZumH3rTCMS1/?ref=app */ #include #include using namespace std; using ull = unsigned long long; bool is_karpekar(ull num) { if(num == 0 || num == 1) return true; if(num == 2 || num == 3) return false; string nstr = to_string(num*num); auto sz = nstr.size(); return stoull(nstr.substr(0,sz/2)) + stoull(nstr.substr(sz/2)) == num; } int main() { ull num; cin >> num; cout << "number " << num << " is Karpekar ? " << boolalpha << is_karpekar(num); }

[Challenge] Karpekar Number.cpp