第一题： vector<vector<int> > invert_tree(int** node_data_list, int node_data_listRowLen, int* node_data_listColLen) { int n = node_data_listRowLen; int root = 0; vector<vector<int> > tree(n+1, vector<int>()); vector<vector<int> > ans; for(int i = 0; i < n; i++) { int id = node_data_list[i][0]; int p = node_data_list[i][1]; if(p == 0) root = id; else tree[p].push_back(id); } for(int i = 1; i <= n; i++) { reverse(tree[i].begin(), tree[i].end()); } ans.push_back({root,0}); dfs(root, 0, tree, ans); return ans; } void dfs(int root, int parent, vector<vector<int> >& tree, vector<vector<int> >& ans) { for(int i = 0; i < tree[root].size(); i++) { ans.push_back({tree[root][i], root}); dfs(tree[root][i], root, tree, ans); } } 详细参考：