minor refactorings

Author: rampatra

src/main/java/com/leetcode/arrays/NestedListWeightSum.java

@@ -4,7 +4,7 @@
 
 /**
  * Level: Easy
- * Problem Link: https://leetcode.com/problems/nested-list-weight-sum/ (premium)
+ * Problem Link: https://leetcode.com/problems/nested-list-weight-sum/
  * Problem Description:
  * Given a nested list of integers, return the sum of all integers in the list weighted by their depth. Each element
  * is either an integer, or a list – whose elements may also be integers or other lists.

src/main/java/com/leetcode/arrays/NestedListWeightSumII.java

@@ -6,7 +6,7 @@
 
 /**
  * Level: Medium
- * Problem Link: https://leetcode.com/problems/nested-list-weight-sum-ii/ (premium)
+ * Problem Link: https://leetcode.com/problems/nested-list-weight-sum-ii/
  * Problem Description:
  * Given a nested list of integers, return the sum of all integers in the list weighted by their depth. Each element
  * is either an integer, or a list – whose elements may also be integers or other lists.

src/main/java/com/leetcode/dynamicprogramming/PaintHouse.java

@@ -2,7 +2,7 @@
 
 /**
  * Level: Easy
- * Problem Link: https://leetcode.com/problems/paint-house/ (premium)
+ * Problem Link: https://leetcode.com/problems/paint-house/
  * Problem Description:
  * There are a row of n houses, each house can be painted with one of the three colors: red, blue or green. The cost
  * of painting each house with a certain color is different. You have to paint all the houses such that no two adjacent

src/main/java/com/leetcode/dynamicprogramming/PaintHouseII.java

@@ -4,7 +4,7 @@
 
 /**
  * Level: Hard
- * Problem Link: https://leetcode.com/problems/paint-house-ii/ (premium)
+ * Problem Link: https://leetcode.com/problems/paint-house-ii/
  * Problem Description:
  * There are a row of n houses, each house can be painted with one of the m colors.
  * The cost of painting each house with a certain color is different.

src/main/java/com/leetcode/maps/ShortestWordDistanceII.java

@@ -9,7 +9,7 @@
 
 /**
  * Level: Medium
- * Problem Link: https://leetcode.com/problems/shortest-word-distance-ii/ (premium)
+ * Problem Link: https://leetcode.com/problems/shortest-word-distance-ii/
  * Problem Description:
  * Design a class which receives a list of words in the constructor, and implements a method that takes two words
  * word1 and word2 and return the shortest distance between these two words in the list. Your method will be called

src/main/java/com/leetcode/trees/ClosestBinarySearchTreeValue.java

@@ -4,7 +4,7 @@
 
 /**
  * Level: Easy
- * Problem Link: https://leetcode.com/problems/closest-binary-search-tree-value/ (premium)
+ * Problem Link: https://leetcode.com/problems/closest-binary-search-tree-value/
  * Problem Description:
  * Given a non-empty binary search tree and a target value, find the value in the BST that is closest to the target.
  * <p>

src/main/java/com/leetcode/trees/ClosestBinarySearchTreeValueII.java

@@ -4,7 +4,7 @@
 
 /**
  * Level: Hard
- * Problem Link: https://leetcode.com/problems/closest-binary-search-tree-value-ii/ (premium)
+ * Problem Link: https://leetcode.com/problems/closest-binary-search-tree-value-ii/
  * Problem Description:
  *
  *