Create consecutive-numbers-sum.py

yingl · web-flow · commit 43a89face2dd · 2022-03-05T22:10:52.000+08:00
diff --git a/consecutive-numbers-sum.py b/consecutive-numbers-sum.py
@@ -0,0 +1,23 @@
+class Solution:
+    """
+    @param n: an integer
+    @return: how many ways can we write it as a sum of consecutive positive integers
+    """
+    def consecutive_numbers_sum(self, n: int) -> int:
+        # Write your code here
+        '''
+        There is a math tricky:
+        1. K = N
+        2. K + K + 1 = N -> 2K = N - 1
+        3. K + K + 1 + K + 2 = N -> 3K = N - 1 - 2
+        '''
+        r = 0
+        i = 1
+        while n > 0:
+            if (n % i) == 0:
+                r += 1
+            n -= i
+            i += 1
+        return r
+      
+# medium: https://www.lintcode.com/problem/1439/
