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August 10, 2020 17:32
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/** | |
* Definition for a binary tree node. | |
* struct TreeNode { | |
* int val; | |
* TreeNode *left; | |
* TreeNode *right; | |
* TreeNode() : val(0), left(nullptr), right(nullptr) {} | |
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {} | |
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {} | |
* }; | |
*/ | |
//BFS-Method | |
class Solution { | |
public: | |
vector<vector<int>> verticalTraversal(TreeNode* root) { | |
TreeNode *curr; | |
queue<pair<TreeNode*, int>> q; | |
q.push({root,0}); | |
vector<vector<int>> ans; | |
map<int,vector<int>> mymap; | |
//BFS | |
while(!q.empty()) | |
{ | |
int size = q.size(); | |
map<int,set<int>> mapset; | |
while(size--) | |
{ | |
curr = q.front().first; | |
int col = q.front().second; | |
q.pop(); | |
mapset[col].insert(curr->val); | |
if(curr->left) | |
q.push({curr->left,col-1}); | |
if(curr->right) | |
q.push({curr->right,col+1}); | |
} | |
for(auto it: mapset) | |
for(auto it2: it.second) | |
mymap[it.first].push_back(it2); | |
} | |
//Now pass all values from mymap to ans array | |
for(auto it: mymap) | |
ans.push_back(it.second); | |
return ans; | |
} | |
}; | |
//DFS Method | |
class Solution { | |
map<int,map<int,set<int>>> mymap; | |
void solve(TreeNode *curr,int col,int row) | |
{ | |
if(!curr) | |
return; | |
mymap[col][row].insert(curr->val); | |
solve(curr->left,col-1,row+1); | |
solve(curr->right,col+1,row+1); | |
} | |
public: | |
vector<vector<int>> verticalTraversal(TreeNode* root) { | |
solve(root,0,0); | |
vector<vector<int>> ans; | |
for(auto m1: mymap) | |
{ | |
ans.push_back(vector<int>()); | |
for(auto m2: m1.second) | |
{ | |
for(auto m3: m2.second) | |
ans.back().push_back(m3); | |
} | |
} | |
return ans; | |
} | |
}; |
@ankush the 2-d vector you talking about is global variable.
Use map<int,map<int,multiset<int>>> mymap;
instead of map<int,map<int,set<int>>> mymap
In case of set
it will give an error because set
cannot have duplicate values.
Use unordered_map<int, unordered_map<int, multiset>> mymap; instead of map<int,map<int,set>> mymap
as unordered map will be faster.
Both the codes are giving error for this test case in leetcode
[3,1,4,0,2,2]
gives output = [[0],[1],[3,2],[4]]
expected output = [[0],[1],[3,2,2],[4]]
https://leetcode.com/problems/vertical-order-traversal-of-a-binary-tree/submissions/
Use multiset instead of set
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how we can store 2-d vector in main function after return and print the values from the main-vector.