501. 二叉搜索树中的众数

题目链接

const getList = (root: TreeNode | null, resList: number[]) => {
    if (!root) return;
    if (root.left) getList(root.left, resList);
    resList.push(root.val);
    if (root.right) getList(root.right, resList);
    return;
}

function findMode(root: TreeNode | null) {
    const valList = [] as number[];
    getList(root, valList);
    let map = {} as {[key:number]:number};
    valList.forEach(it=>{
        if (!map[it])map[it]=0;
        map[it]+=1;
    });
    const maxNum = Math.max(...Object.values(map));
    const res = [] as number[];
    Object.keys(map).forEach(key=>{
        if(map[Number(key)] === maxNum) res.push(Number(key));
    })
    return res;
};