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[LeetCode] Squirrel Simulation 2022-08-27|PSLeetCode|Problem Solving-Math-Greedy

You are given two integers height and width representing a garden of size height x width. You are also given:

an array tree where tree = [treer, treec] is the position of the tree in the garden,

an array squirrel where squirrel = [squirrelr, squirrelc] is the position of the squirrel in the garden,

and an array nuts where nuts[i] = [nutir, nutic] is the position of the ith nut in the garden.

The squirrel can only take at most one nut at one time and can move in four directions: up, down, left, and right, to the adjacent cell.

Return the minimal distance for the squirrel to collect all the nuts and put them under the tree one by one.

The distance is the number of moves.

[LeetCode] Chalkboard XOR Game 2022-08-27|PSLeetCode|Problem Solving-Math-Bit Manipulation

810. Chalkboard XOR Game

You are given an array of integers nums represents the numbers written on a chalkboard.

Alice and Bob take turns erasing exactly one number from the chalkboard, with Alice starting first. If erasing a number causes the bitwise XOR of all the elements of the chalkboard to become 0, then that player loses. The bitwise XOR of one element is that element itself, and the bitwise XOR of no elements is 0.

Also, if any player starts their turn with the bitwise XOR of all the elements of the chalkboard equal to 0, then that player wins.

Return true if and only if Alice wins the game, assuming both players play optimally.

[LeetCode] Split Concatenated Strings 2022-08-27|PSLeetCode|String-Problem Solving

555. Split Concatenated Strings

You are given an array of strings strs. You could concatenate these strings together into a loop, where for each string, you could choose to reverse it or not. Among all the possible loops

Return the lexicographically largest string after cutting the loop, which will make the looped string into a regular one.

Specifically, to find the lexicographically largest string, you need to experience two phases:

Concatenate all the strings into a loop, where you can reverse some strings or not and connect them in the same order as given.

Cut and make one breakpoint in any place of the loop, which will make the looped string into a regular one starting from the character at the cutpoint.

And your job is to find the lexicographically largest one among all the possible regular strings.