updates

Author: wuduhren

problems/python3/best-time-to-buy-and-sell-stock.py

@@ -0,0 +1,10 @@
+class Solution:
+    def maxProfit(self, prices: List[int]) -> int:
+        minPrice = prices[0]
+        ans = 0
+        
+        for i in range(1, len(prices)):
+            ans = max(ans, prices[i]-minPrice)
+            minPrice = min(prices[i], minPrice)
+        
+        return ans

problems/python3/longest-consecutive-sequence.py

@@ -0,0 +1,15 @@
+class Solution:
+    def longestConsecutive(self, nums: List[int]) -> int:
+        numSet = set(nums)
+        ans = 0
+        
+        for num in nums:
+            isStart = num-1 not in numSet
+            if isStart:
+                count = 0
+                temp = num
+                while temp in numSet:
+                    count += 1
+                    temp += 1
+                ans = max(count, ans)
+        return ans

problems/python3/longest-repeating-character-replacement.py

@@ -0,0 +1,13 @@
+class Solution:
+    def characterReplacement(self, s: str, k: int) -> int:
+        counter = collections.Counter()
+        l = 0
+        ans = 0
+        
+        for r in range(len(s)):
+            counter[s[r]] += 1
+            while (r-l+1)-max(counter.values()) > k:
+                counter[s[l]] -= 1
+                l += 1
+            ans = max(ans, r-l+1)
+        return ans

problems/python3/longest-substring-without-repeating-char.py

@@ -0,0 +1,14 @@
+class Solution:
+    def lengthOfLongestSubstring(self, s: str) -> int:
+        ans = 0
+        l = 0
+        seen = set()
+        
+        for r in range(len(s)):
+            while s[r] in seen:
+                seen.remove(s[l])
+                l += 1
+            seen.add(s[r])
+            ans = max(ans, r-l+1)
+        
+        return ans

problems/python3/permutation-in-string.py

@@ -0,0 +1,28 @@
+class Solution:
+    def checkInclusion(self, s1: str, s2: str) -> bool:
+        if len(s1)>len(s2): return False
+        
+        counter1 = collections.Counter(s1)
+        counter2 = collections.Counter(s2[:len(s1)])
+        matches = 0
+        for c in 'abcdefghijklmnopqrstuvwxyz':
+            if counter1[c]==counter2[c]: matches += 1
+        if matches==26: return True
+        
+        l = 0
+        for r in range(len(s1), len(s2)):
+            counter2[s2[r]] += 1
+            if counter1[s2[r]]==counter2[s2[r]]:
+                matches += 1
+            elif counter1[s2[r]]+1==counter2[s2[r]]:
+                matches -= 1
+            
+            counter2[s2[l]] -= 1
+            if counter1[s2[l]]==counter2[s2[l]]:
+                matches += 1
+            elif counter1[s2[l]]-1==counter2[s2[l]]:
+                matches -= 1
+            l += 1
+            
+            if matches==26: return True
+        return False