• 递归练习


    //max值
    function getMaxVal(arr){
        let maxVal=null;
        function loop(arr){
            let [key1,...keys]=arr;
            if(!key1){return}
            maxVal=key1>maxVal?key1:maxVal;
            loop(keys);
        }
        loop(arr)
        return maxVal;
    }
    getMaxVal([9,12,1,3,6])
    
    function getMaxVal1(arr){
        function loop(arr){
            let [key1,...keys]=arr;
            if(!keys.length){return key1}
            return key1>loop(keys)?key1:loop(keys);
        }
        return loop(arr)
    }
    getMaxVal1([9,12,1,3,6])
    let myReverse=(arr)=>{
        let [key1,...keys]=arr;
        if(!keys.length)return [key1]
        return [...myReverse(keys),key1]
    }
    myReverse(['a','b','c'])
    面试题1: 楼梯问题
    假如楼梯有n个台阶,每次可以走1个或2个台阶,请问走完这n个台阶有几种走法?
    那如果有n个台阶呢?我们认真思考下就会发现,第1步的走法有两类:第一种是第一步走1个台阶,
    第二种是第二步走2个台阶。所以n个台阶的走法就可以分为:走完1个台阶后的n
    -1种走法,加上走完2个台阶后的n-2种走法,用递归公式表示就是: function climbStairs(n) { return climbStairs(n - 1) + climbStairs(n - 2) }

    climbStairs(n) = climbStairs(n-1) + climbStairs(n-2)
    climbStairs(n-1) = climbStairs(n-2) + climbStairs(n-3)
    ··· ··· ···
    climbStairs(5) = climbStairs(4) + climbStairs(3)
    climbStairs(4) = climbStairs(3) + climbStairs(2)
    climbStairs(3) = climbStairs(2) + climbStairs(1)
    climbStairs(2) = 2
    climbStairs(1) = 1
    function climbStairs(n) {
      if (n == 1) return 1
      if (n == 2) return 2
      return climbStairs(n-1) + climbStairs(n-2)
    }

     参考:https://juejin.im/post/5d7df6bff265da03b638dc97

    https://www.jb51.net/article/144663.htm

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        }, {
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            "employeeCount": null,
            "children": [{
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    var oneDimensionArr2=function(arr){
        return arr.reduce((pre,cur)=>{
            if(!cur.children)return[]
            return (Array.isArray(cur.children)&&cur.children.length)?[...pre,cur,...this.oneDimensionArr2(cur.children)]:[...pre,cur]
        },[])
    }
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  • 原文地址:https://www.cnblogs.com/little-ab/p/11522983.html
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