음하하하

[Implement strStr()]

https://leetcode.com/problems/implement-strstr/

[Missing Number]

https://leetcode.com/problems/missing-number/

xor operation

[Single Number]

https://leetcode.com/problems/single-number/

xor operation

[Symmetric Tree]

https://leetcode.com/problems/symmetric-tree/

DFS

[Minimum Depth of Binary Tree]

https://leetcode.com/problems/minimum-depth-of-binary-tree/

DFS로 구현, BFS로도 구현 가능

[Excel Sheet Column Number]

https://leetcode.com/problems/excel-sheet-column-number/

math

[Palindrome Partitioning]

https://leetcode.com/problems/palindrome-partitioning/

def dfs(sublist, str)

if not str

ret += sublist

else

for str의 0번 인덱스 시작 길이가 1부터 len(str)까지의 모든 substring

if substring is palindrome

dfs(sublist += substring, str에서 substring을 제외한 나머지)

[Binary Tree Preorder, Inorder, Postorder]

https://leetcode.com/problems/binary-tree-preorder-traversal/

https://leetcode.com/problems/binary-tree-inorder-traversal/

https://leetcode.com/problems/binary-tree-postorder-traversal/

stack, hash

reverse(preorder) = postorder