Create ways-to-split-array-into-three-subarrays.py

Author: kamyu104

Python/ways-to-split-array-into-three-subarrays.py

@@ -0,0 +1,25 @@
+# Time:  O(n)
+# Space: O(n)
+
+class Solution(object):
+    def waysToSplit(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        MOD = 10**9+7
+
+        prefix = [0]
+        for x in nums:
+            prefix.append(prefix[-1]+x)
+
+        result = left = right = 0 
+        for i in xrange(len(nums)): 
+            left = max(left, i+1)
+            while left+1 < len(nums) and prefix[i+1] > prefix[left+1]-prefix[i+1]:
+                left += 1
+            right = max(right, left)
+            while right+1 < len(nums) and prefix[right+1]-prefix[i+1] <= prefix[-1]-prefix[right+1]:
+                right += 1
+            result = (result + (right-left))%MOD
+        return result