MaskRay
diff --git a/‎3sum-closest.cc
+1 b/‎3sum-closest.cc
+1
diff --git a/‎3sum.cc
+1 b/‎3sum.cc
+1
diff --git a/‎4sum.cc
+1 b/‎4sum.cc
+1
diff --git a/‎add-binary.cc
+1 b/‎add-binary.cc
+1
diff --git a/‎add-two-numbers.cc
+1 b/‎add-two-numbers.cc
+1
diff --git a/‎anagrams.cc
+1 b/‎anagrams.cc
+1
diff --git a/‎balanced-binary-tree.cc
+1 b/‎balanced-binary-tree.cc
+1
diff --git a/‎best-time-to-buy-and-sell-stock-ii.cc
+1 b/‎best-time-to-buy-and-sell-stock-ii.cc
+1
diff --git a/‎best-time-to-buy-and-sell-stock-iii.cc
+1 b/‎best-time-to-buy-and-sell-stock-iii.cc
+1
diff --git a/‎best-time-to-buy-and-sell-stock-iv.cc
+1 b/‎best-time-to-buy-and-sell-stock-iv.cc
+1
diff --git a/‎best-time-to-buy-and-sell-stock.cc
+1 b/‎best-time-to-buy-and-sell-stock.cc
+1
diff --git a/‎binary-search-tree-iterator.cc
+1 b/‎binary-search-tree-iterator.cc
+1
diff --git a/‎binary-tree-inorder-traversal.cc
+1 b/‎binary-tree-inorder-traversal.cc
+1
diff --git a/‎binary-tree-level-order-traversal-ii.cc
+1 b/‎binary-tree-level-order-traversal-ii.cc
+1
diff --git a/‎binary-tree-level-order-traversal.cc
+1 b/‎binary-tree-level-order-traversal.cc
+1
diff --git a/‎binary-tree-maximum-path-sum.cc
+1 b/‎binary-tree-maximum-path-sum.cc
+1
diff --git a/‎binary-tree-postorder-traversal.cc
+1 b/‎binary-tree-postorder-traversal.cc
+1
diff --git a/‎binary-tree-preorder-traversal.cc
+1 b/‎binary-tree-preorder-traversal.cc
+1
diff --git a/‎binary-tree-zigzag-level-order-traversal.cc
+1 b/‎binary-tree-zigzag-level-order-traversal.cc
+1
diff --git a/‎candy.cc
+1 b/‎candy.cc
+1
diff --git a/‎climbing-stairs.cc
+1 b/‎climbing-stairs.cc
+1
diff --git a/‎clone-graph.cc
+1 b/‎clone-graph.cc
+1
diff --git a/‎combination-sum-ii.cc
+1 b/‎combination-sum-ii.cc
+1
diff --git a/‎combination-sum.cc
+1 b/‎combination-sum.cc
+1
diff --git a/‎combinations.cc
+1 b/‎combinations.cc
+1
diff --git a/‎compare-version-numbers.cc
+1 b/‎compare-version-numbers.cc
+1
diff --git a/‎construct-binary-tree-from-inorder-and-postorder-traversal.cc
+1 b/‎construct-binary-tree-from-inorder-and-postorder-traversal.cc
+1
diff --git a/‎construct-binary-tree-from-preorder-and-inorder-traversal.cc
+1 b/‎construct-binary-tree-from-preorder-and-inorder-traversal.cc
+1
diff --git a/‎container-with-most-water.cc
+1 b/‎container-with-most-water.cc
+1
diff --git a/‎convert-sorted-array-to-binary-search-tree.cc
+1 b/‎convert-sorted-array-to-binary-search-tree.cc
+1
diff --git a/‎convert-sorted-list-to-binary-search-tree.cc
+1 b/‎convert-sorted-list-to-binary-search-tree.cc
+1
diff --git a/‎copy-list-with-random-pointer.cc
+1 b/‎copy-list-with-random-pointer.cc
+1
diff --git a/‎count-and-say.cc
+1 b/‎count-and-say.cc
+1
diff --git a/‎decode-ways.cc
+1 b/‎decode-ways.cc
+1
diff --git a/‎distinct-subsequences.cc
+1 b/‎distinct-subsequences.cc
+1
diff --git a/‎divide-two-integers.cc
+1 b/‎divide-two-integers.cc
+1
diff --git a/‎dungeon-game.cc
+1 b/‎dungeon-game.cc
+1
diff --git a/‎edit-distance.cc
+1 b/‎edit-distance.cc
+1
diff --git a/‎evaluate-reverse-polish-notation.cc
+1 b/‎evaluate-reverse-polish-notation.cc
+1
diff --git a/‎excel-sheet-column-number.cc
+1 b/‎excel-sheet-column-number.cc
+1
diff --git a/‎excel-sheet-column-title.cc
+1 b/‎excel-sheet-column-title.cc
+1
diff --git a/‎factorial-trailing-zeroes.cc
+1 b/‎factorial-trailing-zeroes.cc
+1
diff --git a/‎find-minimum-in-rotated-sorted-array-ii.cc
+1 b/‎find-minimum-in-rotated-sorted-array-ii.cc
+1
diff --git a/‎find-minimum-in-rotated-sorted-array.cc
+1 b/‎find-minimum-in-rotated-sorted-array.cc
+1
diff --git a/‎find-peak-element.cc
+3-2 b/‎find-peak-element.cc
+3-2
diff --git a/‎first-missing-positive.cc
+1 b/‎first-missing-positive.cc
+1
diff --git a/‎flatten-binary-tree-to-linked-list.cc
+1 b/‎flatten-binary-tree-to-linked-list.cc
+1
diff --git a/‎fraction-to-recurring-decimal.cc
+1 b/‎fraction-to-recurring-decimal.cc
+1
diff --git a/‎gas-station.cc
+1 b/‎gas-station.cc
+1
diff --git a/‎generate-parentheses.cc
+1 b/‎generate-parentheses.cc
+1
diff --git a/‎gray-code.cc
+1 b/‎gray-code.cc
+1
diff --git a/‎implement-strstr.cc
+1 b/‎implement-strstr.cc
+1
diff --git a/‎insert-interval.cc
+1 b/‎insert-interval.cc
+1
diff --git a/‎insertion-sort-list.cc
+1 b/‎insertion-sort-list.cc
+1
diff --git a/‎integer-to-roman.cc
+1 b/‎integer-to-roman.cc
+1
diff --git a/‎interleaving-string.cc
+1 b/‎interleaving-string.cc
+1
diff --git a/‎intersection-of-two-linked-lists.cc
+1 b/‎intersection-of-two-linked-lists.cc
+1
diff --git a/‎jump-game-ii.cc
+1 b/‎jump-game-ii.cc
+1
diff --git a/‎jump-game.cc
+1 b/‎jump-game.cc
+1
diff --git a/‎largest-number.cc
+1 b/‎largest-number.cc
+1
diff --git a/‎largest-rectangle-in-histogram.cc
+1 b/‎largest-rectangle-in-histogram.cc
+1
diff --git a/‎length-of-last-word.cc
+1 b/‎length-of-last-word.cc
+1
diff --git a/‎letter-combinations-of-a-phone-number.cc
+1 b/‎letter-combinations-of-a-phone-number.cc
+1
diff --git a/‎linked-list-cycle-ii.cc
+1 b/‎linked-list-cycle-ii.cc
+1
diff --git a/‎linked-list-cycle.cc
+1 b/‎linked-list-cycle.cc
+1
diff --git a/‎longest-common-prefix.cc
+1 b/‎longest-common-prefix.cc
+1
diff --git a/‎longest-consecutive-sequence.cc
+1 b/‎longest-consecutive-sequence.cc
+1
diff --git a/‎longest-palindromic-substring.cc
+1 b/‎longest-palindromic-substring.cc
+1
diff --git a/‎longest-substring-without-repeating-characters.cc
+1 b/‎longest-substring-without-repeating-characters.cc
+1
diff --git a/‎longest-valid-parentheses.cc
+1 b/‎longest-valid-parentheses.cc
+1
diff --git a/‎lru-cache.cc
+1 b/‎lru-cache.cc
+1
diff --git a/‎majority-element.cc
+1 b/‎majority-element.cc
+1
diff --git a/‎max-points-on-a-line.cc
+1 b/‎max-points-on-a-line.cc
+1
diff --git a/‎maximal-rectangle.cc
+1 b/‎maximal-rectangle.cc
+1
diff --git a/‎maximum-depth-of-binary-tree.cc
+1 b/‎maximum-depth-of-binary-tree.cc
+1
diff --git a/‎maximum-gap.cc
+1 b/‎maximum-gap.cc
+1
diff --git a/‎maximum-product-subarray.cc
+1 b/‎maximum-product-subarray.cc
+1
@@ -1,3 +1,4 @@
+// 3Sum Closest
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// 3Sum
 class Solution {
 public:
   vector<vector<int> > threeSum(vector<int> &a) {
 
@@ -1,3 +1,4 @@
+// 4Sum
 class Solution {
 public:
   vector<vector<int> > fourSum(vector<int> &a, int target) {
 
@@ -1,3 +1,4 @@
+// Add Binary
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Add Two Numbers
 class Solution {
 public:
   ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
 
@@ -1,3 +1,4 @@
+// Anagrams
 class Solution {
 public:
   vector<string> anagrams(vector<string> &strs) {
 
@@ -1,3 +1,4 @@
+// Balanced Binary Tree
 class Solution {
 public:
   bool isBalanced(TreeNode *root) {
 
@@ -1,3 +1,4 @@
+// Best Time to Buy and Sell Stock II
 class Solution {
 public:
   int maxProfit(vector<int> &prices) {
 
@@ -1,3 +1,4 @@
+// Best Time to Buy and Sell Stock III
 class Solution {
 public:
   int maxProfit(vector<int> &prices) {
 
@@ -1,3 +1,4 @@
+// Best Time to Buy and Sell Stock IV
 class Solution {
 public:
   int maxProfit(int k, vector<int> &a) {
 
@@ -1,3 +1,4 @@
+// Best Time to Buy and Sell Stock
 class Solution {
 public:
   int maxProfit(vector<int> &prices) {
 
@@ -1,3 +1,4 @@
+// Binary Search Tree Iterator
 class BSTIterator {
 public:
   stack<TreeNode *> s;
 
@@ -1,3 +1,4 @@
+// Binary Tree Inorder Traversal
 class Solution {
 public:
   vector<int> inorderTraversal(TreeNode *p) {
 
@@ -1,3 +1,4 @@
+// Binary Tree Level Order Traversal II
 class Solution {
 public:
   vector<vector<int> > levelOrderBottom(TreeNode *root) {
 
@@ -1,3 +1,4 @@
+// Binary Tree Level Order Traversal
 class Solution {
 public:
   vector<vector<int> > levelOrder(TreeNode *root) {
 
@@ -1,3 +1,4 @@
+// Binary Tree Maximum Path Sum
 class Solution {
 public:
   int maxPathSum(TreeNode *root) {
 
@@ -1,3 +1,4 @@
+// Binary Tree Postorder Traversal
 class Solution {
 public:
   vector<int> postorderTraversal(TreeNode *p) {
 
@@ -1,3 +1,4 @@
+// Binary Tree Preorder Traversal
 class Solution {
 public:
   vector<int> preorderTraversal(TreeNode *p) {
 
@@ -1,3 +1,4 @@
+// Binary Tree Zigzag Level Order Traversal
 class Solution {
 public:
   vector<vector<int> > zigzagLevelOrder(TreeNode *root) {
 
@@ -1,3 +1,4 @@
+// Candy
 class Solution {
 public:
   int candy(vector<int> &ratings) {
 
@@ -1,3 +1,4 @@
+// Climbing Stairs
 class Solution {
 public:
   int climbStairs(int n) {
 
@@ -1,3 +1,4 @@
+// Clone Graph
 class Solution {
 public:
   UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) {
 
@@ -1,3 +1,4 @@
+// Combination Sum II
 class Solution {
 private:
   void f(vector<vector<int>> &r, vector<int> &rr, vector<int> &a, int i, int s) {
 
@@ -1,3 +1,4 @@
+// Combination Sum
 class Solution {
 private:
   void f(vector<vector<int>> &r, vector<int> &rr, vector<int> &a, int i, int s) {
 
@@ -1,3 +1,4 @@
+// Combinations
 // Matters Computational: Ideas, Algorithms, Source Code 6.3
 // prefix shifts
 
 
@@ -1,3 +1,4 @@
+// Compare Version Numbers
 class Solution {
 public:
   int compareVersion(string a, string b) {
 
@@ -1,3 +1,4 @@
+// Construct Binary Tree from Inorder and Postorder Traversal
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Construct Binary Tree from Preorder and Inorder Traversal
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Container With Most Water
 class Solution {
 public:
   int maxArea(vector<int> &h) {
 
@@ -1,3 +1,4 @@
+// Convert Sorted Array to Binary Search Tree
 class Solution {
 public:
   TreeNode *sortedArrayToBST(vector<int> &a) {
 
@@ -1,3 +1,4 @@
+// Convert Sorted List to Binary Search Tree
 class Solution {
 public:
   TreeNode *sortedListToBST(ListNode *head) {
 
@@ -1,3 +1,4 @@
+// Copy List with Random Pointer
 class Solution {
 public:
   RandomListNode *copyRandomList(RandomListNode *head) {
 
@@ -1,3 +1,4 @@
+// Count and Say
 #define REP(i, n) for (int i = 0; i < (n); i++)
 #define REP1(i, n) for (int i = 1; i <= (n); i++)
 
 
@@ -1,3 +1,4 @@
+// Decode Ways
 #define FOR(i, a, b) for (int i = (a); i < (b); i++)
 #define ROF(i, a, b) for (int i = (b); --i >= (a); )
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
@@ -1,3 +1,4 @@
+// Distinct Subsequences
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 #define REP1(i, n) FOR(i, 1, n+1)
 
@@ -1,3 +1,4 @@
+// Divide Two Integers
 class Solution {
 public:
   int divide(int p, int q) {
 
@@ -1,3 +1,4 @@
+// Dungeon Game
 // 進入當前格子時最少需要的血量(尚未考慮當前格子影響)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Edit Distance
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Evaluate Reverse Polish Notation
 class Solution {
 public:
     int evalRPN(vector<string> &tokens) {
 
@@ -1,3 +1,4 @@
+// Excel Sheet Column Number
 class Solution {
 public:
   int titleToNumber(string s) {
 
@@ -1,3 +1,4 @@
+// Excel Sheet Column Title
 class Solution {
 public:
   string convertToTitle(int n) {
 
@@ -1,3 +1,4 @@
+// Factorial Trailing Zeroes
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Find Minimum in Rotated Sorted Array II
 class Solution {
 public:
   int findMin(vector<int> &a) {
 
@@ -1,3 +1,4 @@
+// Find Minimum in Rotated Sorted Array
 class Solution {
 public:
   int findMin(vector<int> &a) {
 
@@ -1,12 +1,13 @@
+// Find Peak Element
 class Solution {
 public:
   int findPeakElement(const vector<int> &a) {
     int l = 0, h = a.size();
     while (l < h-1) {
       int m = l+h >> 1;
       if (a[m-1] > a[m]) h = m;
-      else if (m+1 == h || a[m] > a[m+1]) l = h = m;
-      else l = m+1;
+      else if (m+1 == h || a[m] < a[m+1]) l = m;
+      else l = h = m;
     }
     return l;
   }
 
@@ -1,3 +1,4 @@
+// First Missing Positive
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Flatten Binary Tree to Linked List
 class Solution {
 public:
   void flatten(TreeNode *root) {
 
@@ -1,3 +1,4 @@
+// Fraction to Recurring Decimal
 class Solution {
 public:
   string fractionToDecimal(int aa, int bb) {
 
@@ -1,3 +1,4 @@
+// Gas Station
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Generate Parentheses
 // Matters Computational: Ideas, Algorithms, Source Code 15.3
 // prefix shifts
 
 
@@ -1,3 +1,4 @@
+// Gray Code
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Implement strStr()
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Insert Interval
 class Solution {
 public:
   vector<Interval> insert(vector<Interval> &xs, Interval x) {
 
@@ -1,3 +1,4 @@
+// Insertion Sort List
 #define FOR(i, a, b) for (int(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Integer to Roman
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Interleaving String
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Intersection of Two Linked Lists
 class Solution {
 public:
   ListNode *getIntersectionNode(ListNode *a, ListNode *b) {
 
@@ -1,3 +1,4 @@
+// Jump Game II
 #define FOR(i, a, b) for (int i = (a); i < (b); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Jump Game
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Largest Number
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Largest Rectangle in Histogram
 #define REP(i, n) for (int i = 0; i < (n); i++)
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Length of Last Word
 class Solution {
 public:
   int lengthOfLastWord(const char *s) {
 
@@ -1,3 +1,4 @@
+// Letter Combinations of a Phone Number
 class Solution {
 private:
   string a;
 
@@ -1,3 +1,4 @@
+// Linked List Cycle II
 // Brent's cycle detection
 
 class Solution {
 
@@ -1,3 +1,4 @@
+// Linked List Cycle
 class Solution {
 public:
   bool hasCycle(ListNode *head) {
 
@@ -1,3 +1,4 @@
+// Longest Common Prefix
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Longest Consecutive Sequence
 class Solution {
 public:
   int longestConsecutive(vector<int> &num) {
 
@@ -1,3 +1,4 @@
+// Longest Palindromic Substring
 // Manacher's algorithm
 
 #define FOR(i, a, b) for (decltype(b) i = (a); i < (b); i++)
 
@@ -1,3 +1,4 @@
+// Longest Substring Without Repeating Characters
 class Solution {
 public:
   int lengthOfLongestSubstring(string s) {
 
@@ -1,3 +1,4 @@
+// Longest Valid Parentheses
 class Solution {
 public:
   int longestValidParentheses(string s) {
 
@@ -1,3 +1,4 @@
+// LRU Cache
 class LRUCache {
 public:
   LRUCache(int capacity) : c(capacity) {}
 
@@ -1,3 +1,4 @@
+// Majority Element
 class Solution {
 public:
   int majorityElement(vector<int> &a) {
 
@@ -1,3 +1,4 @@
+// Max Points on a Line
 #define FOR(i, a, b) for (__typeof(b) i = (a); i < (b); i++)
 #define REP(i, n) FOR(i, 0, n)
 
 
@@ -1,3 +1,4 @@
+// Maximal Rectangle
 // 秋叶拓哉（iwi）、岩田阳一（wata）和北川宜稔（kita_masa）所著，巫泽俊（watashi）、庄俊元（navi）和李津羽（itsuhane）翻译的《挑战程序设计竞赛》
 
 #define ROF(i, a, b) for (int i = (b); --i >= (a); )
 
@@ -1,3 +1,4 @@
+// Maximum Depth of Binary Tree
 class Solution {
 public:
   int maxDepth(TreeNode *root) {
 
@@ -1,3 +1,4 @@
+// Maximum Gap
 class Solution {
 public:
   int maximumGap(vector<int> &a) {
 
@@ -1,3 +1,4 @@
+// Maximum Product Subarray
 #define FOR(i, a, b) for (int i = (a); i < (b); i++)
 
 class Solution {
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// 3Sum Closest`
`1`	`2`	`#define REP(i, n) for (int i = 0; i < (n); i++)`
`2`	`3`
`3`	`4`	`class Solution {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// 3Sum`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`vector<vector<int> > threeSum(vector<int> &a) {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// 4Sum`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`vector<vector<int> > fourSum(vector<int> &a, int target) {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// Add Binary`
`1`	`2`	`#define REP(i, n) for (int i = 0; i < (n); i++)`
`2`	`3`
`3`	`4`	`class Solution {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// Add Two Numbers`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`ListNode addTwoNumbers(ListNode l1, ListNode *l2) {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// Anagrams`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`vector<string> anagrams(vector<string> &strs) {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// Balanced Binary Tree`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`bool isBalanced(TreeNode *root) {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// Best Time to Buy and Sell Stock II`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`int maxProfit(vector<int> &prices) {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// Best Time to Buy and Sell Stock III`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`int maxProfit(vector<int> &prices) {`
Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,4 @@`
	`1`	`+// Best Time to Buy and Sell Stock IV`
`1`	`2`	`class Solution {`
`2`	`3`	`public:`
`3`	`4`	`int maxProfit(int k, vector<int> &a) {`