add 102, 965, 1876

Author: rustykitty

102-binary-tree-level-order-traversal.cpp

@@ -0,0 +1,41 @@
+/*
+102. Binary Tree Level Order Traversal
+
+Submitted: January 13, 2024
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 17.24 MB (beats 14.20%)
+*/
+
+/**
+ * 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) {}
+ * };
+ */
+class Solution {
+public:
+    vector<vector<int>> levelOrder(TreeNode* root) {
+        if (root == nullptr) return {};
+        vector<vector<int>> res;
+        deque<TreeNode*> queue;
+        queue.push_front(root);
+        while (!queue.empty()) {
+            vector<int> v;
+            for (int i = 0, n = queue.size(); i < n; ++i) {
+                TreeNode* p = queue.back();
+                queue.pop_back();
+                v.push_back(p->val);
+                if (p->left != nullptr) queue.push_front(p->left);
+                if (p->right != nullptr) queue.push_front(p->right);
+            }
+            res.push_back(v);
+        }
+        return res;
+    }
+};

1876-substrings-of-size-three-with-distinct-characters.cpp

@@ -0,0 +1,25 @@
+/*
+1876. Substrings of Size Three with Distinct Characters
+
+Submitted: January 13, 2024
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 8.37 MB (beats 73.21%)
+*/
+
+class Solution {
+public:
+    int countGoodSubstrings(string s) {
+        if (s.size() < 3) return 0;
+        // char arr[3];
+        int res = 0;
+        for (int i = 0, n = s.size() - 2; i < n; ++i) {
+            res += (
+                s[i] != s[i + 1] && s[i] != s[i + 2] &&
+                s[i + 1] != s[i] && s[i + 1] != s[i + 2] &&
+                s[i + 2] != s[i] && s[i + 2] != s[i + 1]
+            );
+        }
+        return res;
+    }
+};

1876-substrings-of-size-three-with-distinct-characters.py

@@ -0,0 +1,12 @@
+"""
+1876. Substrings of Size Three with Distinct Characters
+
+Submitted: January 13, 2024
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 17.72 MB (beats 21.15%)
+"""
+
+class Solution:
+    def countGoodSubstrings(self, s: str) -> int:
+        return sum(len(set(s[x:x+3])) == 3 for x in range(0, len(s) - 2))

965-univalued-binary-tree.cpp

@@ -0,0 +1,31 @@
+/*
+965. Univalued Binary Tree
+
+Submitted: January 13, 2024
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 12.69 MB (beats 29.98%)
+*/
+
+/**
+ * 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) {}
+ * };
+ */
+
+class Solution {
+public:
+    int val = -1;
+    bool isUnivalTree(TreeNode* root) {
+        if (root == nullptr) return true;
+        if (val == -1) val = root->val;
+        if (root->val != val) return false;
+        return isUnivalTree(root->left) && isUnivalTree(root->right);
+    }
+};