Create valid-square.py

Author: kamyu104

Python/valid-square.py

@@ -0,0 +1,34 @@
+# Time:  O(1)
+# Space: O(1)
+
+# Given the coordinates of four points in 2D space,
+# return whether the four points could construct a square.
+#
+# The coordinate (x,y) of a point is represented by an integer array with two integers.
+#
+# Example:
+# Input: p1 = [0,0], p2 = [1,1], p3 = [1,0], p4 = [0,1]
+# Output: True
+# Note:
+#
+# All the input integers are in the range [-10000, 10000].
+# A valid square has four equal sides with positive length
+# and four equal angles (90-degree angles).
+# Input points have no order.
+
+class Solution(object):
+    def validSquare(self, p1, p2, p3, p4):
+        """
+        :type p1: List[int]
+        :type p2: List[int]
+        :type p3: List[int]
+        :type p4: List[int]
+        :rtype: bool
+        """
+        def dist(p1, p2):
+            return (p1[0] - p2[0]) ** 2 + (p1[1] - p2[1]) ** 2
+
+        counter = collections.Counter([dist(p1, p2), dist(p1, p3),\
+                                       dist(p1, p4), dist(p2, p3),\
+                                       dist(p2, p4), dist(p3, p4)])
+        return 0 not in counter and len(counter) == 2