add some array playing

arrays_and_strings/array-3rd-distinct-0n.py

@@ -0,0 +1,41 @@
+'''
+Given an integer array nums, return the third distinct maximum 
+number in this array. If the third maximum does not exist, 
+return the maximum number.
+
+Do it O(n).
+'''
+
+import math
+
+
+def thirdMax(nums: list[int]) -> int:
+        
+        first_max = -math.inf
+        second_max = -math.inf
+        third_max = -math.inf
+        
+        for n in nums:
+            
+            if n == first_max or n == second_max or n == third_max:
+                continue
+            elif n > first_max:
+                third_max = second_max
+                second_max = first_max
+                first_max = n
+            elif n > second_max:
+                third_max = second_max
+                second_max = n
+            elif n > third_max:
+                third_max = n
+        
+        if third_max == -math.inf:
+            third_max = max(second_max, first_max)
+                
+        return third_max
+
+
+if __name__ == "__main__":
+
+    nums = [3,2,1]
+    assert(thirdMax(nums) == 1)