Create the-number-of-weak-characters-in-the-game.py

Author: kamyu104

Python/the-number-of-weak-characters-in-the-game.py

@@ -0,0 +1,38 @@
+# Time:  O(nlogn)
+# Space: O(1)
+
+class Solution(object):
+    def numberOfWeakCharacters(self, properties):
+        """
+        :type properties: List[List[int]]
+        :rtype: int
+        """
+        properties.sort(cmp=lambda a, b: cmp(b[1], a[1]) if a[0] == b[0] else cmp(a[0], b[0]))
+        result = max_d = 0
+        for a, d in reversed(properties):
+            if d < max_d:
+                result += 1
+            max_d = max(max_d, d)
+        return result
+
+    
+# Time:  O(nlogn)
+# Space: O(n)
+import collections
+
+
+# faster in sort by using more space
+class Solution(object):
+    def numberOfWeakCharacters(self, properties):
+        """
+        :type properties: List[List[int]]
+        :rtype: int
+        """
+        lookup = collections.defaultdict(list)
+        for a, d in properties:
+            lookup[a].append(d)
+        result = max_d = 0
+        for a in sorted(lookup.iterkeys(), reverse=True):
+            result += sum(d < max_d for d in lookup[a])
+            max_d = max(max_d, max(lookup[a]))
+        return result