515 leetcode

C++/515_Find_Largest_value_in_each_tree_row.cpp

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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) {}
+ * };
+ */
+// TC -O(N) N-> Number of nodes in a tree
+// SC -O(W)We W-> maximum number of nodes possible at one time in queue
+// so basically the number of nodes maximum in a row.
+//DIFFICULTY-MEDIUM
+class Solution {
+public:
+ vector<int> largestValues(TreeNode* root) {
+ vector<int> ans;
+ if(root==NULL) return ans;
+ if(root->left==NULL && root->right==NULL)
+ {
+ ans.push_back(root->val);
+ return ans;
+ }
+ queue<TreeNode*> q;
+ q.push(root);
+ while(q.empty()==false)
+ {
+ int n=q.size();
+ int maximum_val= INT_MIN;
+ while(n--)
+ {
+ TreeNode *curr =q.front();
+ q.pop();
+ if(maximum_val < curr->val)
+ maximum_val=curr->val;
+ if(curr->left!=NULL)
+ q.push(curr->left);
+ if(curr->right!=NULL)
+ q.push(curr->right);
+ }
+ ans.push_back(maximum_val);
+ }
+ return ans;
+ }
+};