update

Author: kamyu104

Python/two-sum-iii-data-structure-design.py

@@ -0,0 +1,45 @@
+# Time:  O(n)
+# Space: O(n)
+#
+# Design and implement a TwoSum class. It should support the following operations: add and find.
+# 
+# add - Add the number to an internal data structure.
+# find - Find if there exists any pair of numbers which sum is equal to the value.
+# 
+# For example,
+# add(1); add(3); add(5);
+# find(4) -> true
+# find(7) -> false
+#
+
+class TwoSum:
+
+    # initialize your data structure here
+    def __init__(self):
+        self.lookup = {}
+        
+
+    # @return nothing
+    def add(self, number):
+        if number in self.lookup:
+            self.lookup[number] += 1
+        else:
+            self.lookup[number] = 1
+
+    # @param value, an integer
+    # @return a Boolean
+    def find(self, value):
+        for key in self.lookup:
+            num = value - key
+            if num in self.lookup and (num != key or self.lookup[key] > 1):
+                return True
+        return False
+
+if __name__ == "__main__":
+    Sol = TwoSum()
+    for i in (1, 3, 5):
+        Sol.add(i)
+    for i in (4, 7):
+        print Sol.find(i)
+                
+                

README.md

@@ -265,6 +265,7 @@ Problem         |  Solution       |  Time           | Space           | Difficul
 [Minimum Window Substring] | [minimum-window-substring.py] | _O(n^2)_ | _O(n)_ | Hard          |
 [Substring with Concatenation of All Words] | [substring-with-concatenation-of-all-words.py] | _O(m * n * k)_ | _O(n * k)_ | Hard          |
 [Two Sum]      | [two-sum.py]      | _O(n)_         | _O(n)_          | Medium         |
+[Two Sum III - Data structure design] | [two-sum-iii-data-structure-design.py] | _O(n)_ | _O(n)_ | Easy |
 [Valid Sudoku] | [valid-sudoku.py] | _O(n)_         | _O(n)_          | Easy           |
 
 [4 Sum]: https://oj.leetcode.com/problems/4sum/
@@ -281,6 +282,8 @@ Problem         |  Solution       |  Time           | Space           | Difficul
 [substring-with-concatenation-of-all-words.py]:https://github.com/kamyu104/LeetCode/blob/master/Python/substring-with-concatenation-of-all-words.py
 [Two Sum]:https://oj.leetcode.com/problems/two-sum/
 [two-sum.py]:https://github.com/kamyu104/LeetCode/blob/master/Python/two-sum.py
+[Two Sum III - Data structure design]:https://oj.leetcode.com/problems/two-sum-iii-data-structure-design/
+[two-sum-iii-data-structure-design.py]:https://github.com/kamyu104/LeetCode/blob/master/Python/two-sum-iii-data-structure-design.py
 [Valid Sudoku]:https://oj.leetcode.com/problems/valid-sudoku/
 [valid-sudoku.py]:https://github.com/kamyu104/LeetCode/blob/master/Python/valid-sudoku.py