leetcode/all-nodes-distance-k-in-binary-tree.cpp at master · amitbansal7/leetcode · GitHub

Name: leetcode/all-nodes-distance-k-in-binary-tree.cpp at master · amitbansal7/leetcode · GitHub
Rating: 4.7 (5714 reviews)
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//Runtime: 7 ms
classSolution {
public:

voidtoGraph(TreeNode* root, map<int, vector<int> >&adj) {
 vector<int> t;
if (root->left) {
 adj[root->val].push_back(root->left->val);
 adj[root->left->val].push_back(root->val);
toGraph(root->left, adj);
 }
if (root->right) {
 adj[root->val].push_back(root->right->val);
 adj[root->right->val].push_back(root->val);
toGraph(root->right, adj);
 }

 }

voiddfs(map<int, vector<int> >&adj, int tar, int dis, vector<int> &res, set<int> &vis) {
if (vis.find(tar) != vis.end()) return;
if (dis == 0) res.push_back(tar);
if (dis <= 0) return;

if (vis.find(tar) == vis.end()) {
 vis.insert(tar);

for (int a : adj[tar]) {
dfs(adj, a, dis - 1, res, vis);
 }
 }

 }

 vector<int> distanceK(TreeNode* root, TreeNode* target, int K) {
 map<int, vector<int> > adj;

toGraph(root, adj);

 vector<int> res;
 set<int> vis;
dfs(adj, target->val, K, res, vis);
return res;
 }
};