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해피넘버

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각 단계 번호가 해당 숫자의 제곱합으로 대체되는 일련의 단계 후에 1이 되는 숫자, 즉 Happy Number로 시작하여 숫자 제곱합으로 계속 바꾸면 1에 도달하는 숫자를 행복이라고 합니다. 

예:  



Input: n = 19  
Output: True
19 is Happy Number
1^2 + 9^2 = 82
8^2 + 2^2 = 68
6^2 + 8^2 = 100
1^2 + 0^2 + 0^2 = 1
As we reached to 1 19 is a Happy Number.

Input: n = 20
Output: False

이미 터치된 숫자에 연속적으로 닿는 등 순서대로 루프를 만드는 숫자는 해피 넘버가 아닙니다. 따라서 숫자가 행복한지 여부를 확인하기 위해 동일한 숫자가 다시 발생하면 결과를 행복하지 않은 것으로 표시하여 세트를 유지할 수 있습니다. 위 접근 방식의 간단한 함수는 다음과 같이 작성할 수 있습니다.  

C++
// method return true if n is Happy Number int numSquareSum(int n) {  int num = 0;  while (n != 0) {  int digit = n % 10;  num += digit * digit;  n /= 10;  }  return num; } int isHappyNumber(int n) {  set<int> st;  while (1)  {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.find(n) != st.end())  return false;  st.insert(n);  } } 
Java
// method return true if n is Happy Number public static int numSquareSum(int n) {  int num = 0;  while (n != 0) {  int digit = n % 10;  num += digit * digit;  n /= 10;  }  return num; } static boolean isHappyNumber(int n) {  HashSet<Integer> st = new HashSet<>();  while (true) {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.contains(n))  return false;  st.add(n);  } } // This code is contributed by Princi Singh 
Python
# method return true if n is Happy Number def numSquareSum(n): num = 0 while(n): digit = n % 10 num = num + digit*digit n = n // 10 return num def isHappyNumber(n): st = set() while (1): n = numSquareSum(n) if (n == 1): return True if n not in st: return False st.insert(n) 
C#
// Method return true if n is Happy Number static int numSquareSum(int n) {  int num = 0;  while (n != 0) {  int digit = n % 10;  num += digit * digit;  n /= 10;  }  return num; } static int isHappyNumber(int n) {  HashSet<int> st = new HashSet<>();  while (1) {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.Contains(n))  return false;  st.Add(n);  } } // This code is contributed by 29AjayKumar 
JavaScript
<script> // method return true if n is Happy Number  function numSquareSum(n) {  let num = 0;  while (n !== 0) {  let digit = n % 10;  num += digit * digit;  n = Math.floor(n / 10);  }  return num;  }  let st = new Set();  while (1)  {  n = numSquareSum(n);  if (n == 1)  return true;  if (st.has(n))  return false;  st.add(n);  } } //This code is contributed by Mayank Tyagi </script> 

복잡성 분석:

시간 복잡도: O(n*log(n)). 
보조 공간: O(n) 저장용으로 별도의 세트를 사용한 이후



추가 공간을 사용하지 않고도 이 문제를 해결할 수 있으며 해당 기술은 다른 유사한 문제에도 사용할 수 있습니다. 모든 숫자를 노드로 취급하고 제곱합 숫자를 링크로 대체하면 이 문제는 다음과 같습니다. 링크리스트에서 루프 찾기

따라서 위 링크에서 제안된 솔루션으로 우리는 두 개의 숫자를 느리고 빠르게 유지합니다. 둘 다 주어진 숫자에서 초기화합니다. 느린 것은 한 번에 한 단계씩 교체되고, 빠른 것은 한 번에 두 단계씩 교체됩니다. 그들이 1시에 만나면 주어진 숫자는 Happy Number이고, 그렇지 않으면 그렇지 않습니다.  

C++
// C++ program to check a number is a Happy number or not #include    using namespace std; // Utility method to return sum of square of digit of n int numSquareSum(int n) {  int squareSum = 0;  while (n) {  squareSum += (n % 10) * (n % 10);  n /= 10;  }  return squareSum; } // method return true if n is Happy number bool isHappynumber(int n) {  int slow fast;  // initialize slow and fast by n  slow = fast = n;  do {  // move slow number by one iteration  slow = numSquareSum(slow);  // move fast number by two iteration  fast = numSquareSum(numSquareSum(fast));  } while (slow != fast);  // if both number meet at 1 then return true  return (slow == 1); } // Driver code to test above methods int main() {  int n = 13;  if (isHappynumber(n))  cout << n << ' is a Happy numbern';  else  cout << n << ' is not a Happy numbern'; } // This code is contributed by divyeshrabadiya07 
C
// C program to check a number is a Happy number or not #include  #include  // Utility method to return sum of square of digit of n int numSquareSum(int n) {  int squareSum = 0;  while (n) {  squareSum += (n % 10) * (n % 10);  n /= 10;  }  return squareSum; } // method return true if n is Happy number bool isHappynumber(int n) {  int slow fast;  // initialize slow and fast by n  slow = fast = n;  do {  // move slow number by one iteration  slow = numSquareSum(slow);  // move fast number by two iteration  fast = numSquareSum(numSquareSum(fast));  } while (slow != fast);  // if both number meet at 1 then return true  return (slow == 1); } // Driver code to test above methods int main() {  int n = 13;  if (isHappynumber(n))  printf('%d is a Happy numbern' n);  else  printf('%d is not a Happy numbern' n); } // This code is contributed by Sania Kumari Gupta // (kriSania804) 
Java
// Java program to check a number is a Happy // number or not class GFG {   // Utility method to return sum of square of // digit of n static int numSquareSum(int n) {  int squareSum = 0;  while (n!= 0)  {  squareSum += (n % 10) * (n % 10);  n /= 10;  }  return squareSum; }   // method return true if n is Happy number static boolean isHappynumber(int n) {  int slow fast;    // initialize slow and fast by n  slow = fast = n;  do  {  // move slow number  // by one iteration  slow = numSquareSum(slow);    // move fast number  // by two iteration  fast = numSquareSum(numSquareSum(fast));    }  while (slow != fast);    // if both number meet at 1  // then return true  return (slow == 1); }   // Driver code to test above methods public static void main(String[] args) {  int n = 13;  if (isHappynumber(n))  System.out.println(n +   ' is a Happy number');  else  System.out.println(n +   ' is not a Happy number'); } } 
Python
# Python3 program to check if a number is a Happy number or not # Utility method to return the sum of squares of digits of n def num_square_sum(n): square_sum = 0 while n: square_sum += (n % 10) ** 2 n //= 10 return square_sum # Method returns True if n is a Happy number def is_happy_number(n): # Initialize slow and fast pointers slow = n fast = n while True: # Move slow pointer by one iteration slow = num_square_sum(slow) # Move fast pointer by two iterations fast = num_square_sum(num_square_sum(fast)) if slow != fast: continue else: break # If both pointers meet at 1 then return True return slow == 1 # Driver Code n = 13 if is_happy_number(n): print(n 'is a Happy number') else: print(n 'is not a Happy number') 
C#
// C# program to check a number // is a Happy number or not using System; class GFG { // Utility method to return  // sum of square of digit of n static int numSquareSum(int n) {  int squareSum = 0;  while (n!= 0)  {  squareSum += (n % 10) *   (n % 10);  n /= 10;  }  return squareSum; } // method return true if // n is Happy number static bool isHappynumber(int n) {  int slow fast;  // initialize slow and  // fast by n  slow = fast = n;  do  {    // move slow number  // by one iteration  slow = numSquareSum(slow);  // move fast number  // by two iteration  fast = numSquareSum(numSquareSum(fast));  }  while (slow != fast);  // if both number meet at 1  // then return true  return (slow == 1); } // Driver code public static void Main() {  int n = 13;  if (isHappynumber(n))  Console.WriteLine(n +   ' is a Happy number');  else  Console.WriteLine(n +   ' is not a Happy number'); } } // This code is contributed by anuj_67. 
JavaScript
<script> // Javascript program to check a number is a Happy // number or not // Utility method to return sum of square of // digit of n function numSquareSum(n) {  var squareSum = 0;  while (n!= 0)  {  squareSum += (n % 10) * (n % 10);  n = parseInt(n/10);  }  return squareSum; }   // method return true if n is Happy number function isHappynumber(n) {  var slow fast;    // initialize slow and fast by n  slow = fast = n;  do  {  // move slow number  // by one iteration  slow = numSquareSum(slow);    // move fast number  // by two iteration  fast = numSquareSum(numSquareSum(fast));    }  while (slow != fast);    // if both number meet at 1  // then return true  return (slow == 1); }   // Driver code to test above methods var n = 13; if (isHappynumber(n))  document.write(n +   ' is a Happy number'); else  document.write(n +   ' is not a Happy number');   // This code contributed by Princi Singh  </script> 
PHP
 // PHP program to check a number // is a Happy number or not // Utility method to return  // sum of square of digit of n function numSquareSum( $n) { $squareSum = 0; while ($n) { $squareSum += ($n % 10) * ($n % 10); $n /= 10; } return $squareSum; } // method return true if // n is Happy number function isHappynumber( $n) { $slow; $fast; // initialize slow  // and fast by n $slow = $n; $fast = $n; do { // move slow number // by one iteration $slow = numSquareSum($slow); // move fast number // by two iteration $fast = numSquareSum(numSquareSum($fast)); } while ($slow != $fast); // if both number meet at 1  // then return true return ($slow == 1); } // Driver Code $n = 13; if (isHappynumber($n)) echo $n  ' is a Happy numbern'; else echo n  ' is not a Happy numbern'; // This code is contributed by anuj_67. ?> 

출력 :  



13 is a Happy Number

복잡성 분석:

시간 복잡도: O(n*log(n)).
보조 공간: 오(1). 


추가 공간을 사용하지 않고 이 문제를 해결하는 또 다른 접근 방식입니다.
숫자는 행복한 숫자가 될 수 없습니다 어떤 단계에서든 얻은 자릿수 제곱의 합이 1이나 7을 제외한 한 자리 숫자인 경우 . 1과 7이 유일한 한자리 행복한 숫자이기 때문이다. 이 정보를 사용하여 아래 코드와 같은 접근 방식을 개발할 수 있습니다. 

C++
// C++ program to check if a number is a Happy number or // not. #include    using namespace std; // Method - returns true if the input is a happy number else // returns false bool isHappynumber(int n) {  int sum = n x = n;  // This loop executes till the sum of square of digits  // obtained is not a single digit number  while (sum > 9) {  sum = 0;  // This loop finds the sum of square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 7 || sum == 1)  return true;  return false; } int main() {  int n = 13;  if (isHappynumber(n))  cout << n << ' is a Happy number';  else  cout << n << ' is not a Happy number';  return 0; } // This code is contributed by Sania Kumari Gupta 
C
// C program to check if a number is a Happy number or // not. #include  #include  // Method - returns true if the input is a happy number else // returns false bool isHappynumber(int n) {  int sum = n x = n;  // This loop executes till the sum of square of digits  // obtained is not a single digit number  while (sum > 9) {  sum = 0;  // This loop finds the sum of square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 7 || sum == 1)  return true;  return false; } int main() {  int n = 13;  if (isHappynumber(n))  printf('%d is a Happy number' n);  else  printf('%d is not a Happy number' n);  return 0; } // This code is contributed by Sania Kumari Gupta 
Java
// This code is contributed by Vansh Sodhi. // Java program to check if a number is a Happy number or // not. class GFG {  // method - returns true if the input is a happy  // number else returns false  static boolean isHappynumber(int n)  {  int sum = n x = n;  // this loop executes till the sum of square of  // digits obtained is not a single digit number  while (sum > 9) {  sum = 0;  // this loop finds the sum of square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 1 || sum == 7)  return true;  return false;  }  // Driver code  public static void main(String[] args)  {  int n = 13;  if (isHappynumber(n))  System.out.println(n + ' is a Happy number');  else  System.out.println(n  + ' is not a Happy number');  } } 
Python
# Python3 program to check if a number is a Happy number or not. # Method - returns true if the input is # a happy number else returns false def isHappynumber(n): Sum x = n n # This loop executes till the sum # of square of digits obtained is # not a single digit number while Sum > 9: Sum = 0 # This loop finds the sum of # square of digits while x > 0: d = x % 10 Sum += d * d x = int(x / 10) x = Sum if Sum == 1 or Sum == 7: return True return False n = 13 if isHappynumber(n): print(n 'is a Happy number') else: print(n 'is not a Happy number') # This code is contributed by mukesh07. 
C#
// C# program to check if a number // is a Happy number or not. using System; class GFG {  // Method - returns true if the input is  // a happy number else returns false  static bool isHappynumber(int n)  {  int sum = n x = n;  // This loop executes till the sum  // of square of digits obtained is  // not a single digit number  while (sum > 9) {  sum = 0;  // This loop finds the sum of  // square of digits  while (x > 0) {  int d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if (sum == 1 || sum == 7)  return true;  return false;  }  // Driver code  public static void Main(String[] args)  {  int n = 13;  if (isHappynumber(n))  Console.WriteLine(n + ' is a Happy number');  else  Console.WriteLine(n + ' is not a Happy number');  } } // This code is contributed by 29AjayKumar 
JavaScript
<script> // This code is contributed by Vansh Sodhi. // javascript program to check if a number is a Happy number or not.  // method - returns true if the input is a happy  // number else returns false  function isHappynumber(n)  {  var sum = n x = n;  // this loop executes till the sum of square of  // digits obtained is not a single digit number  while(sum > 9)   {  sum = 0;  // this loop finds the sum of square of digits  while (x > 0)   {  var d = x % 10;  sum += d * d;  x /= 10;  }  x = sum;  }  if(sum == 1 || sum == 7)  return true;  return false; } // Driver code  var n = 13;  if (isHappynumber(n))  document.write(n +   ' is a Happy number');  else  document.write(n +   ' is not a Happy number');   // This code is contributed by 29AjayKumar  </script> 

산출
13 is a Happy number

복잡성 분석:

시간 복잡도: O(n*log(n)).
보조 공간: 오(1). 

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