basic math

3^5 three to the power of five

2^n two to the power of n

<= less than or equal to

modulus求余 mod the number by 2

interval 区间

negative infinity

parentheses.) 括号

remainder 余数

other words

yeah excellent excellent happy to do it sure

amortize ['æmɚtaɪz]

多线程multithreading

死循环 infinite loop

Fibonacci[,fibə'na:si]

degenerate

preprocessing

recursive iterative backtracking

In my understanding, backtracking is an algorithm, like all the other algorithms, like BFS and DFS, but recursion and also iteration are methods, they are at a higher level than the algorithms, for example, to implement a DFS, you can use recursion, which is quite intuitive, but you can also use iteration with a stack, or you can also think recursion and iteration are just methods to support your algorithms.

eulerian/orerien/ path

extra storage

clockwise / counter clockwise

during test:so we come back to here, which is our starting setup again

i don't exactly remember the syntax of this, but I think it's something like this.

升序排列in an ascending order 按降序排in a descending order

lexicographical词典编纂的

enumerate枚举

strickthrough

consecutive continuous

O(nm) so the complicity would be n times m

then we will try the same thing with the number on the left, and we will repeat this process over and over again until...

so now we are just in the state we want to be

and finally if we get through the whole thing and they are all equal to each other, we know that it's the ans, we just return true

dash-

square brackets[]

Bit

用一个二进制什么鬼usedis the 9-bit bitmask telling which keys have already been used

shift to left by 2

we can do it easily by doing a bitwise xor

Tree

Pre-order/ In-order/Post-order travese

everything on the right side of the tree ..