Revert "Revert "Leetcode""

This reverts commit f2d28c8b85b9b6fce43b0977463e72d4547afc81.
Revert "Leetcode"

This reverts commit f2e7a28a9f8e766edf681cb25eeb0ccf5e09a52d.
part of the accepted Leetode codes

algorithm and data stuct of Leetcode
Revert "Revert "Leetcode""

This reverts commit 8a1bfd47ea095eb607578dacf8ecad48ad5d9f70.
Revert "Revert "Revert "Leetcode"""

This reverts commit 7ef0d9430d65b2d2a391ccd48c224c0356b795e1.