[:solved] house-robber

Author: ppxyn1

house-robber/ppxyn1.py

@@ -0,0 +1,20 @@
+# idea: DP Top-down / Bottom-up
+# DP was comp up on my head, but it is not easy for me to utilse recursive function. 
+
+
+class Solution:
+    def rob(self, nums: List[int]) -> int:
+        length = len(nums)
+        if length == 0:
+            return 0
+        if length == 1:
+            return nums[0]
+
+        lst = [0]*length 
+        lst[0] = nums[0]
+        lst[1] = max(nums[0], nums[1])
+
+        for i in range(2, length):
+            lst[i] = max(lst[i-1], lst[i-2] + nums[i])
+
+        return lst[-1]

longest-consecutive-sequence/ppxyn1.py

@@ -1,17 +1,35 @@
 # idea: - 
+
 class Solution:
     def longestConsecutive(self, nums: List[int]) -> int:
-        sorted_nums = sorted(list(set(nums))) 
-        # sorted_nums = sorted(nums) # duplicate
-        max_len = 1
-        tmp = 1
-
-        for i in range(1, len(sorted_nums)):
-            if sorted_nums[i] == sorted_nums[i - 1] + 1:
-                tmp += 1
-            else:
-                max_len = max(max_len, tmp)
-                tmp = 1 
-        ans = max(max_len, tmp)
-        return  ans
+        ans = 0
+        return ans
+
+
+
+'''
+Trial and error
+
+The code below was passed on Leecode since their Constraints was 0 <= nums.length <= 10^5.
+But I realised that I missed another constraint they mentioned, which is "You must write an algorithm that runs in O(n) time."
+'''
+# class Solution:
+#     def longestConsecutive(self, nums: List[int]) -> int:
+#         if len(nums)==0:
+#             return 0
+#         sorted_nums = sorted(list(set(nums))) 
+#         # sorted_nums = sorted(nums) # duplicate
+#         max_len = 1
+#         tmp = 1
+
+#         for i in range(1, len(sorted_nums)):
+#             if sorted_nums[i] == sorted_nums[i - 1] + 1:
+#                 tmp += 1
+#             else:
+#                 max_len = max(max_len, tmp)
+#                 tmp = 1 
+#         ans = max(max_len, tmp)
+#         return  ans
+
+