Repeated sum of digits

Author: anantkaushik

Python/GeeksforGeeks/repeated-sum-of-digits.py

@@ -0,0 +1,44 @@
+"""
+Problem Link: https://practice.geeksforgeeks.org/problems/repeated-sum-of-digits/0
+
+Given an integer N, recursively sum digits of N until we get a single digit.  The process can be described below
+If N < 10    
+    digSum(N) = N
+Else         
+    digSum(N) = Sum(digSum(N))
+
+Example:
+Input : 1234
+Output : 1
+Explanation : The sum of 1+2+3+4 = 10, 
+              digSum(x) == 10
+              Hence ans will be 1+0 = 1
+
+Input:
+The first line contains an integer T, total number of test cases. Then following T lines contains an integer N.
+
+Output:
+Repeated sum of digits of N.
+
+Constraints:
+1 ≤ T ≤ 100
+1 ≤ N ≤ 1000000
+
+Example:
+Input
+2
+123
+9999
+
+Output
+6
+9
+"""
+for _ in range(int(input())):
+    n = int(input())
+    if n == 0:
+        print(0)
+    elif n % 9 == 0:
+        print(9)
+    else:
+        print(n%9)