代码如下: 问题, vector<int> father=vector<int>(n,0);不报错,而使用vector<int> father(n,0);报错未定义的n?为什么?class Solution {private:int n=200005;vector<int> father=vector<int>(n,0);// vector<int> father(n,0);void init(){for(int i=0;i<n;i++){father[i]=i;}}int find(int u){return u==father[u]?u:find(father[u]);}bool isSame(int u,int v){u=find(u);v=find(v);return u==v;}void join(int u,int v){u=find(u);v=find(v);if(u==v) return;father[v]=u;}public:bool validPath(int nn, vector<vector<int>>&amp; edges, int source, int destination) {init();for(int i=0;i<edges.size();i++){join(edges[i][0],edges[i][1]);}return isSame(source,destination);}};