Hard Challenge 25

25 Hard problems for advanced interview preparation.

25 道題目

#	題目	難度	Rating
1	4. Median of Two Sorted Arrays	Hard	2028
2	10. Regular Expression Matching	Hard	2025
3	23. Merge K Sorted Lists	Hard	1893
4	25. Reverse Nodes in k-Group	Hard	2011
5	30. Substring with Concatenation of All Words	Hard	2039
6	32. Longest Valid Parentheses	Hard	2118
7	37. Sudoku Solver	Hard	2313
8	41. First Missing Positive	Hard	1944
9	42. Trapping Rain Water	Hard	2062
10	44. Wildcard Matching	Hard	2100
11	51. N-Queens	Hard	1797
12	52. N-Queens II	Hard	1843
13	60. Permutation Sequence	Hard	1953
14	65. Valid Number	Hard	1892
15	72. Edit Distance	Medium	1703
16	76. Minimum Window Substring	Hard	1890
17	84. Largest Rectangle in Histogram	Hard	1949
18	85. Maximal Rectangle	Hard	2188
19	87. Scramble String	Hard	2264
20	97. Interleaving String	Medium	1785
21	115. Distinct Subsequences	Hard	1849
22	124. Binary Tree Maximum Path Sum	Hard	1807
23	140. Word Break II	Hard	2081
24	212. Word Search II	Hard	1976
25	295. Find Median from Data Stream	Hard	1973