Leetcode Round 4 记录

完全没有思路

1. Sudoku Solver

2. Unique BST II [递归思路]

3. Sorted List to BST [O(n)时间复杂度]

4. Surrounded Regions [DFS转BFS]

5. palindrome partitioning II [dp递推式]

6. Gas Station []

7. Candy [{4， 2， 3， 4， 1}]

8. Best Time to Buy and Sell Stock IV [dp状态转移方程]

9. Minimum Size Subarray Sum [两指针方法，注意记录最小值]

10. Contains Duplicate III [TreeSet数据结构]

 

提交多次才通过

1. Palindrome Number

2. Regular Expression Matching

3. Jump Game II [贪心的条件]

4. Decode Ways [110, 100, 0]

5. Clone Graph [BFS过程中，如何将未被访问过的node加入到queue中]

6. Repeated DNA Sequence [编码方式， 输出结果判重]

7. Course Schedule I [最小堆, bfs]

8. Word Search II [Trie优化，注意存visited矩阵]

 

小陷阱题

1. First Missing Positive Number. [死循环的case: {1, 1}]

2. Sqrt [int相乘要使用long来存储，防止越界]

3. reverse words [双指针法]