first time unsolved

1. string reorder distant apart. reference: http://discuss.leetcode.com/questions/31/string-reorder-distance-apart

2. Excel sheet numbers. reference: done but not perfect. reference: http://discuss.leetcode.com/questions/64/excel-sheet-row-numbers

3. Search 2D array 3 questions, know how to slove the problem in a common way, but need to polish.

   reference:  http://discuss.leetcode.com/questions/67/searching-a-2d-sorted-matrix-part-i (part1)

                   http://discuss.leetcode.com/questions/70/searching-a-2d-sorted-matrix-part-ii (part2)

                   http://discuss.leetcode.com/questions/73/searching-a-2d-sorted-matrix-part-iii (part3)

4.post traversal without recursion: http://discuss.leetcode.com/questions/82/binary-tree-post-order-traversal-iterative-solution

5. http://discuss.leetcode.com/questions/106/largest-binary-search-tree-bst-in-a-binary-tree

6. http://discuss.leetcode.com/questions/124/peg-game-problem-analysis

7. http://discuss.leetcode.com/questions/130/nuts-in-an-oasis

8. know how to do but have a problem with the answer http://discuss.leetcode.com/questions/133/sliding-window-maximum