Create degree-of-an-array.py

Author: kamyu104

Python/degree-of-an-array.py

@@ -0,0 +1,42 @@
+# Time:  O(n)
+# Space: O(n)
+
+# Given a non-empty array of non-negative integers nums,
+# the degree of this array is defined as the maximum frequency of any one of its elements.
+#
+# Your task is to find the smallest possible length of a (contiguous) subarray of nums,
+# that has the same degree as nums.
+#
+# Example 1:
+# Input: [1, 2, 2, 3, 1]
+# Output: 2
+# Explanation: 
+# The input array has a degree of 2 because both elements 1 and 2 appear twice.
+# Of the subarrays that have the same degree:
+# [1, 2, 2, 3, 1], [1, 2, 2, 3], [2, 2, 3, 1], [1, 2, 2], [2, 2, 3], [2, 2]
+# The shortest length is 2. So return 2.
+#
+# Example 2:
+# Input: [1,2,2,3,1,4,2]
+# Output: 6
+# Note:
+#
+# nums.length will be between 1 and 50,000.
+# nums[i] will be an integer between 0 and 49,999.
+
+class Solution(object):
+    def findShortestSubArray(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        counts = collections.Counter(nums)
+        left, right = {}, {}
+        for i, num in enumerate(nums):
+            left.setdefault(num, i)
+            right[num] = i
+        degree = max(counts.values())
+        return min(right[num]-left[num]+1 \
+                   for num in counts.keys() \
+                   if counts[num] == degree)
+