排序与树的遍历算法实现

// 冒泡
function sort1(arr){
  for ( let i=0, len=arr.length; i<len-1; i++ ){
    for ( let j=i+1; j<=len-1; j++ ){
      if ( arr[i] > arr[j] ){
        let tmp = arr[i];
        arr[i] = arr[j];
        arr[j] = tmp;
      }
    }
  }
  return arr;
}

// 插入
function sort2(arr){
  for ( let i=1, len=arr.length; i<=len-1; i++ ){
    var tmp = arr[i];
    for ( var j=i-1; j>=0; j-- ){
      if ( arr[j] > tmp ){
        arr[j+1] = arr[j];
      }
      else {
        break ;
      }
    }
    arr[j+1] = tmp;
  }
  return arr;
}

// 快排
function part(arr, start, end){
  let pivot = arr[start];
  while (start < end) {
    while (start < end && arr[end] > pivot) {
      --end;
    }
    arr[start] = arr[end];
    while (start < end && arr[start] <= pivot) {
      ++start;
    }
    arr[end] = arr[start];
  }
  arr[start] = pivot;
  return start;
}

function sort3(arr, start, end){
  if ( start >= end ) return arr;
  let index = part(arr, start, end);
  sort3(arr, start, index-1);
  sort3(arr, index+1, end)
  return arr;
}
function sort(arr){
  return sort3(arr,0,arr.length-1)
}

---

const tree = {
  value : 1,
  children: [
    {value:'1-1', children:[{value:'1-1-1',children:[]}]},
    {value:'1-2', children:[{value:'1-2-1', children:[{value:'1-2-1-1'}]},{value:'1-2-2',children:[]}]},
    {value:'1-3', children:[{value:'1-3-1'},{value:'1-3-2'}]}
  ]
}

// 广度优先
function spread(tree){
  var nodeArr = [];
  var valArr = [];

  nodeArr.push(tree);
  while ( nodeArr.length > 0 ){
    let node = nodeArr.shift();
    valArr.push(node.value);
    node.children && node.children.map(v=>{
      nodeArr.push(v);
    });
  }
  return valArr;
}

// 深度优先
function deep(tree){
  let nodeArr = [], valArr = [];
  nodeArr.push(tree);
  while ( nodeArr.length > 0 ){
    let node = nodeArr.shift();
    valArr.push(node.value);
    if ( node.children ){
      for ( let len=node.children.length-1; len>=0 ;len-- ){
        nodeArr.unshift(node.children[len]);
      }
    }
  }
  return valArr;
}