Update to 016

Update to 016

Author: nature1995

Python3/004_Median_of_Two_Sorted_Arrays.py

@@ -1,11 +1,10 @@
 #!usr/bin/env python
 # -*- coding:utf-8 -*-
-
-
 '''
 There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).
 '''
 
+
 class Solution(object):
     def findMedianSortedArrays(self, nums1, nums2):
         """

Python3/009_Palindrome_Number.py

@@ -1,7 +1,5 @@
 #!usr/bin/env python
 # -*- coding:utf-8 -*-
-
-
 '''
 Determine whether an integer is a palindrome. Do this without extra space.
 
@@ -14,6 +12,7 @@
 There is a more generic way of solving this problem.
 '''
 
+
 class Solution(object):
     def isPalindrome(self, x):
         """

Python3/012_Integer_to_Roman.py

@@ -1,7 +1,32 @@
 #!usr/bin/env python
 # -*- coding:utf-8 -*-
+'''
+Given an integer, convert it to a roman numeral.
 
+Input is guaranteed to be within the range from 1 to 3999.
+'''
 
 
+class Solution(object):
+    def intToRoman(self, num):
+        """
+        :type num: int
+        :rtype: str
+        """
+        nums = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1]
+        strings = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"]
+        result = ''
+        for i in range(len(nums)):
+            while num >= nums[i]:
+                num -= nums[i]
+                result += strings[i]
+        return result
+
+
+# Test cases
+if __name__ == "__main__":
+    assert Solution().intToRoman(12) == "XII"
+    assert Solution().intToRoman(21) == "XXI"
+    assert Solution().intToRoman(99) == "XCIX"
 
 

Python3/013_Roman_to_Integer.py

@@ -1,6 +1,34 @@
 #!usr/bin/env python
 # -*- coding:utf-8 -*-
+'''
+Given a roman numeral, convert it to an integer.
 
+Input is guaranteed to be within the range from 1 to 3999.
+'''
+
+
+class Solution(object):
+    def romanToInt(self, s):
+        """
+        :type s: str
+        :rtype: int
+        """
+        map = {"M": 1000, "D": 500, "C": 100, "L": 50, "X": 10, "V": 5, "I": 1}
+        result = 0
+        for i in range(len(s)):
+            if i > 0 and map[s[i]] > map[s[i-1]]:
+                result -= map[s[i-1]]
+                result += map[s[i]] - map[s[i-1]]
+            else:
+                result += map[s[i]]
+        return result
+
+
+# Test cases
+if __name__ == "__main__":
+    assert Solution().romanToInt("XII") == 12
+    assert Solution().romanToInt("XXI") == 21
+    assert Solution().romanToInt("LVIII") == 58