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  1. #include <iostream>
  2. using namespace std;
  3. /*
  4. Input: n = 19
  5. Output: true
  6. Explanation:12 + 92 = 82
  7. 82 + 22 = 68
  8. 62 + 82 = 100
  9. 12 + 02 + 02 = 1
  10. */
  11. int func1(int n) {
  12. 	int sum = 0;
  13.  
  14. 	while( n > 0) {
  15. 		int digit = n % 10;
  16. 		sum = sum + (digit * digit);
  17. 		n = n / 10;
  18. 	}
  19.  
  20. 	return sum;
  21. }
  22.  
  23. bool isHappy(int n) {
  24. 	int slow = n;
  25.  
  26. 	int fast = func1(n);
  27.  
  28. 	while(fast != 1 && slow != fast) {
  29. 		slow = func1(slow);
  30. 		fast = func1(func1(fast));
  31. 	}
  32. 	if(fast == 1)
  33. 		return true;
  34. 	else
  35. 		return false;
  36. }
  37.  
  38. int main() {
  39. 	int n;
  40. 	cin>>n;
  41. 	cout<< isHappy(n)<<endl;
  42. 	return 0;
  43. }
Success #stdin #stdout 0s 5320KB
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https://ideone.com/GM8Jxv
language:
C++ (gcc 8.3)
created:
1 day ago
visibility:
public

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