Summary of force deduction questions

Code details

Array

1、 Encountered array related problems , It is necessary to judge the boundary conditions

Array sorting

// Array forward sort 
    nums.sort(function(a,b){
    
        return a - b
    })

Generate 26 The first value is 0 Array of

const characters = Array(26).fill(0)

Array to string

const key = characters.join()

Declare a binary array

	const memo = []
    for (let i = 0;i <n;i++){
    
        memo.push([])
    }

Traversal string

//  Define two pointers 
    let left = 0
    let right = s.length - 1
    // Traversal string 
    while(left < right){
    
        if(s[left] !== s[right]){
    
            return false
        }
        left++
        right--
    }

Use regular expressions to remove non letters from strings

\W Find non word characters

s = s.toLowerCase().replace(/[\W_]/g,"")

Split characters with extended strings ：

let s = "anagra"
console.log([...s]);

Output is :['a', 'n', 'a', 'g', 'r', 'a']
Then you can sort the characters ：

[...s].sort()

Output ：['a', 'a', 'a', 'g', 'n', 'r']
adopt [...s].sort().join('') Form a string