Done Hashing 2

problem1.py

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+# LEETCODE PROBLEM 560 SUBARRAY SUM EQUALS K
+# TIME COMPLEXITY:O(N) where N is the number of elements
+# SPACE COMPLEXITY: O(N) where N is the space required to make a hashmap of N elements
+# Any problem you faced while coding this: None
+
+class Solution(object):
+    def subarraySum(self, nums, k):
+        """
+        :type nums: List[int]
+        :type k: int
+        :rtype: int
+        """
+        map={0:1}
+        runningSum=0
+        count=0
+        for i in range(len(nums)):
+            runningSum+=nums[i]
+            diff=runningSum-k
+            if diff in map:
+                count+=map[diff]
+            map[runningSum]=map.get(runningSum,0)+1
+        return count
+

problem2.py

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+# LEETCODE PROBLEM 525 CONTIGUOUS ARRAY
+# TIME COMPLEXITY: O(N) where N is the number of elements
+# SPACE COMPLEXITY: O(N) given that we need to initiate a hashmap for N elements 
+# Any problem you faced while coding this: None
+
+class Solution(object):
+    def findMaxLength(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        runningSum=0
+        map={0:-1}
+        result=0
+        for i in range(len(nums)):
+            if nums[i]==0:
+                runningSum-=1
+            else:
+                runningSum+=1
+            if runningSum in map:
+                result=max(result,i-map[runningSum])
+            else:
+                map[runningSum]=i
+        return result

problem3.py

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+# LEETCODE PROBLEM 409 LONGEST PALINDROME
+# TIME COMPLEXITY: O(N) where N is the number of elements in a given array
+# SPACE COMPLEXITY: O(1) 
+# Any problem you faced while coding this: None
+
+class Solution(object):
+    def longestPalindrome(self, s):
+        """
+        :type s: str
+        :rtype: int
+        """
+        set_char=set()
+        count=0
+
+        for i in s:
+            if i in set_char:
+                count+=2
+                set_char.remove(i)
+            else:
+                set_char.add(i)
+        if len(set_char)>0:
+            return count+1
+        return count
+