题解 | #二叉搜索树的最近公共祖先#

 * function TreeNode(x) {
 *   this.val = x;
 *   this.left = null;
 *   this.right = null;
 * }
 */
//发现找数字大小规律太乱了，那就找结构规律，反正也要按结构索引
function lowestCommonAncestor( root ,  p ,  q ) {
    // write code here
    let res=[]
    let res1=[]
    res1.push('t')
    res1.push(root)
    res.push(res1)
    let resp=''
    let resq=''
    let sum=2
    while(res.length!=0){
        let p1=res.pop()
        if(p1[1].val==p){resp=p1[0];sum--;console.log(resp)}
        if(p1[1].val==q){resq=p1[0];sum--;console.log(resq)}
        if(sum>0){
            if(p1[1].left!=null){
                let b=[]
                b[0]=p1[0]+'l'
                b.push(p1[1].left)
                res.push(b)
            }
            if(p1[1].right!=null){
                let b=[]
                b[0]=p1[0]+'r'
                b.push(p1[1].right)
                res.push(b)
            }
        }
        else{break;}
    }
    let max=resp.length
    if(resq.length>resp.length){max=resq.length}
    for(let i=0;i<max;i++){
        console.log(i)
        if(i>resq.length-1||resp[i]!=resq[i]){
            if(i==1){return root.val}
            let p2=root
            for(let j=1;j<i;j++){
                if(resp[j]=='l'){
                    p2=p2.left
                }
                else if(resp[j]=='r'){
                    p2=p2.right
                }
            }
            return p2.val
        }
    }
    return null
}
module.exports = {
    lowestCommonAncestor : lowestCommonAncestor
};