Merge pull request #3 from adhocore/code

Author: adhocore

README.md

@@ -3,15 +3,19 @@
 Just some (n|l)eet code solutions in Python.
 
 - [Container with max water](./containermaxwater.py)
+- [Eval reverse Polish notation](./evalrpn.py)
 - [Group anagrams together](./groupanagrams.py)
 - [Is Anagram](./isanagram.py)
 - [Longest consecutive seq](./longestconsecutiveseq.py)
+- [Longest non repeat substr len](./longestsubstrlen.py)
 - [Product except self](./productexceptself.py)
 - [Stock max profit - single txn](./stockmaxprofit.py)
+- [String permutations as substring](./substrpermute.py)
 - [Three sum to zero](./threesumzero.py)
 - [Top K frequent items](./topkfrequent.py)
 - [Trap rain water](./traprainwater.py)
 - [Two sum to target](./twosum.py)
+- [Valid parentheses](./validparens.py)
 
 ## Running
 

evalrpn.py

@@ -0,0 +1,29 @@
+class Solution(object):
+    def evalRPN(self, tokens):
+        stak = []
+        for i in range(len(tokens)):
+            if not tokens[i] in "+-*/":
+                stak.append(int(tokens[i]))
+                continue
+            a, b = stak.pop(), stak.pop()
+            if tokens[i] == "+":
+                stak.append(b + a)
+            elif tokens[i] == "-":
+                stak.append(b - a)
+            elif tokens[i] == "*":
+                stak.append(b * a)
+            elif tokens[i] == "/":
+                stak.append(int(b / a))
+        return stak.pop()
+
+
+if __name__ == "__main__":
+    s = Solution()
+    print(s.evalRPN(["2", "1", "+", "3", "*"]))
+    # => 9 => (2+1)*3
+    print(
+        s.evalRPN(["10", "6", "9", "3", "+", "-11", "*", "/", "*", "17", "+", "5", "+"])
+    )
+    # => 22
+    print(s.evalRPN(["4", "-2", "/", "2", "-3", "-", "-"]))
+    # => -7

longestsubstrlen.py

@@ -0,0 +1,19 @@
+class Solution:
+    def lengthOfLongestSubstring(self, s):
+        left, right, maxl, win = 0, 0, 0, {}
+        while right < len(s):
+            if not win.get(s[right]):
+                win[s[right]] = (True,)
+                maxl = max(right - left + 1, maxl)
+            else:
+                while s[left] != s[right]:
+                    win[s[left]], left = False, left + 1
+                left += 1
+            right += 1
+        return maxl
+
+
+if __name__ == "__main__":
+    s = Solution()
+    print(s.lengthOfLongestSubstring("abcdabecbb"))
+    # => 5 => cdabe

substrpermute.py

@@ -0,0 +1,19 @@
+class Solution:
+    def checkStrPermuteSub(self, s1, s2):
+        s1c, s2c = {}, {}
+        for c in s1:
+            s1c[c] = s1c.get(c, 0) + 1
+        for c in s2:
+            if c in s1c:
+                s2c[c] = s2c.get(c, 0) + 1
+                if s1c == s2c:
+                    return True
+            else:
+                s2c = {}
+        return False
+
+
+if __name__ == "__main__":
+    s = Solution()
+    print(s.checkStrPermuteSub("abcd", "zdcbax"))
+    # => True

validparens.py

@@ -0,0 +1,16 @@
+class Solution:
+    def isValidParens(self, s):
+        stak = []
+        pair = {")": "(", "}": "{", "]": "["}
+        for c in s:
+            if c == "(" or c == "{" or c == "[":
+                stak.append(c)
+            elif stak.pop() != pair[c]:
+                return False
+        return len(stak) == 0
+
+
+if __name__ == "__main__":
+    s = Solution()
+    print(s.isValidParens("([]{})"))
+    # => True