Create ways-to-make-a-fair-array.py

Author: kamyu104

Python/ways-to-make-a-fair-array.py

@@ -0,0 +1,17 @@
+# Time:  O(n)
+# Space: O(1)
+
+class Solution(object):
+    def waysToMakeFair(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        prefix = [0]*2
+        suffix = [sum(nums[i] for i in xrange(k, len(nums), 2)) for k in xrange(2)]
+        result = 0
+        for i, num in enumerate(nums):
+            suffix[i%2] -= num
+            result += int(prefix[0]+suffix[1] == prefix[1]+suffix[0])
+            prefix[i%2] += num
+        return result