Create count-number-of-pairs-with-absolute-difference-k.py

Author: kamyu104

Python/count-number-of-pairs-with-absolute-difference-k.py

@@ -0,0 +1,19 @@
+# Time:  O(n)
+# Space: O(n)
+
+class Solution(object):
+    def countKDifference(self, nums, k):
+        """
+        :type nums: List[int]
+        :type k: int
+        :rtype: int
+        """
+        lookup = collections.defaultdict(int)
+        result = 0
+        for x in nums:
+            if x-k in lookup:
+                result += lookup[x-k]
+            if x+k in lookup:
+                result += lookup[x+k]
+            lookup[x] += 1            
+        return result