Merge branch 'neetcode-gh:main' into adityacpp

adityaiiitr · web-flow · commit cee440bb4db0 · 2024-02-06T22:38:19.000+05:30
diff --git a/README.md b/README.md
@@ -260,12 +260,12 @@ If you would like to have collaborator permissions on the repo to merge your own
 <sub>[0129 - Sum Root to Leaf Numbers](https://leetcode.com/problems/sum-root-to-leaf-numbers/)</sub> | <sub><div align='center'>[✔️](c%2F0129-sum-root-to-leaf-numbers.c)</div></sub> | <sub><div align='center'>[✔️](cpp%2F0129-sum-root-to-leaf-numbers.cpp)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F0129-sum-root-to-leaf-numbers.java)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0129-sum-root-to-leaf-numbers.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
 <sub>[0337 - House Robber III](https://leetcode.com/problems/house-robber-iii/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F0337-house-robber-iii.java)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0337-house-robber-iii.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
 <sub>[0951 - Flip Equivalent Binary Trees](https://leetcode.com/problems/flip-equivalent-binary-trees/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F0951-flip-equivalent-binary-trees.java)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0951-flip-equivalent-binary-trees.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
-<sub>[1993 - Operations On Tree](https://leetcode.com/problems/operations-on-tree/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F1993-operations-on-tree.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
+<sub>[1993 - Operations On Tree](https://leetcode.com/problems/operations-on-tree/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F1993-operations-on-tree.java)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F1993-operations-on-tree.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
 <sub>[0894 - All Possible Full Binary Trees](https://leetcode.com/problems/all-possible-full-binary-trees/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F0894-all-possible-full-binary-trees.java)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0894-all-possible-full-binary-trees.kt)</div></sub> | <sub><div align='center'>[✔️](python%2F0894-all-possible-full-binary-trees.py)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
 <sub>[0513 - Find Bottom Left Tree Value](https://leetcode.com/problems/find-bottom-left-tree-value/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F0513-find-bottom-left-tree-value.java)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0513-find-bottom-left-tree-value.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
 <sub>[0669 - Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](go%2F0669-trim-a-binary-search-tree.go)</div></sub> | <sub><div align='center'>[✔️](java%2F0669-trim-a-binary-search-tree.java)</div></sub> | <sub><div align='center'>[✔️](javascript%2F0669-trim-a-binary-search-tree.js)</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0669-trim-a-binary-search-tree.kt)</div></sub> | <sub><div align='center'>[✔️](python%2F0669-trim-a-binary-search-tree.py)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](typescript%2F0669-trim-a-binary-search-tree.ts)</div></sub>
 <sub>[0173 - Binary Search Tree Iterator](https://leetcode.com/problems/binary-search-tree-iterator/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F0173-binary-search-tree-iterator.java)</div></sub> | <sub><div align='center'>[✔️](javascript%2F0173-binary-search-tree-iterator.js)</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0173-binary-search-tree-iterator.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
-<sub>[0538 - Convert Bst to Greater Tree](https://leetcode.com/problems/convert-bst-to-greater-tree/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](cpp%2F0538-convert-bst-to-greater-tree.cpp)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0538-convert-bst-to-greater-tree.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
+<sub>[0538 - Convert Bst to Greater Tree](https://leetcode.com/problems/convert-bst-to-greater-tree/)</sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](cpp%2F0538-convert-bst-to-greater-tree.cpp)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](java%2F0538-convert-bst-to-greater-tree.java)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0538-convert-bst-to-greater-tree.kt)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub>
 <sub>[0124 - Binary Tree Maximum Path Sum](https://leetcode.com/problems/binary-tree-maximum-path-sum/)</sub> | <sub><div align='center'>[✔️](c%2F0124-binary-tree-maximum-path-sum.c)</div></sub> | <sub><div align='center'>[✔️](cpp%2F0124-binary-tree-maximum-path-sum.cpp)</div></sub> | <sub><div align='center'>[✔️](csharp%2F0124-binary-tree-maximum-path-sum.cs)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](go%2F0124-binary-tree-maximum-path-sum.go)</div></sub> | <sub><div align='center'>[✔️](java%2F0124-binary-tree-maximum-path-sum.java)</div></sub> | <sub><div align='center'>[✔️](javascript%2F0124-binary-tree-maximum-path-sum.js)</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0124-binary-tree-maximum-path-sum.kt)</div></sub> | <sub><div align='center'>[✔️](python%2F0124-binary-tree-maximum-path-sum.py)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](rust%2F0124-binary-tree-maximum-path-sum.rs)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](swift%2F0124-binary-tree-maximum-path-sum.swift)</div></sub> | <sub><div align='center'>[✔️](typescript%2F0124-binary-tree-maximum-path-sum.ts)</div></sub>
 <sub>[0297 - Serialize And Deserialize Binary Tree](https://leetcode.com/problems/serialize-and-deserialize-binary-tree/)</sub> | <sub><div align='center'>[✔️](c%2F0297-serialize-and-deserialize-binary-tree.c)</div></sub> | <sub><div align='center'>[✔️](cpp%2F0297-serialize-and-deserialize-binary-tree.cpp)</div></sub> | <sub><div align='center'>[✔️](csharp%2F0297-serialize-and-deserialize-binary-tree.cs)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](go%2F0297-serialize-and-deserialize-binary-tree.go)</div></sub> | <sub><div align='center'>[✔️](java%2F0297-serialize-and-deserialize-binary-tree.java)</div></sub> | <sub><div align='center'>[✔️](javascript%2F0297-serialize-and-deserialize-binary-tree.js)</div></sub> | <sub><div align='center'>[✔️](kotlin%2F0297-serialize-and-deserialize-binary-tree.kt)</div></sub> | <sub><div align='center'>[✔️](python%2F0297-serialize-and-deserialize-binary-tree.py)</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>❌</div></sub> | <sub><div align='center'>[✔️](swift%2F0297-serialize-and-deserialize-binary-tree.swift)</div></sub> | <sub><div align='center'>[✔️](typescript%2F0297-serialize-and-deserialize-binary-tree.ts)</div></sub>
 
diff --git a/java/0049-group-anagrams.java b/java/0049-group-anagrams.java
@@ -1,3 +1,31 @@
+class Solution {
+    public List<List<String>> groupAnagrams(String[] strs) {
+        Map<String, List<String>> res = new HashMap<>();
+
+        for (String s : strs) {
+            int[] count = new int[26];
+
+            for (char c : s.toCharArray()) {
+                count[c - 'a']++;
+            }
+
+            StringBuilder sb = new StringBuilder();
+            for (int i = 0; i < 26; i++) {
+                sb.append('#');
+                sb.append(count[i]);
+            }
+            String key = sb.toString();
+            
+            if (!res.containsKey(key)) {
+                res.put(key, new ArrayList<>());
+            }
+            res.get(key).add(s);
+        }
+
+        return new ArrayList<>(res.values());
+    }
+}
+-------------------------------------------------------------------------
 class Solution {
     public List<List<String>> groupAnagrams(String[] strs) {
         Map<String, List<String>> map = new HashMap<>();
diff --git a/java/0538-convert-bst-to-greater-tree.java b/java/0538-convert-bst-to-greater-tree.java
@@ -0,0 +1,43 @@
+// Recursive solution
+class Solution {
+    private int curSum = 0;
+
+    public TreeNode convertBST(TreeNode root) {
+         convertBSTRecursive(root);
+         return root;
+    }
+
+    private void convertBSTRecursive(TreeNode node) {
+        if (node == null) {
+            return;
+        }
+
+        convertBSTRecursive(node.right);
+        int temp = node.val;
+        node.val += curSum;
+        curSum += temp;
+        convertBSTRecursive(node.left);
+    }
+}
+
+// Iterative solution
+class Solution {
+    public TreeNode convertBST(TreeNode root) {
+        Stack<TreeNode> stack = new Stack<>();
+        TreeNode cur = root;
+
+        int curSum = 0;
+        while (cur != null || !stack.isEmpty()) {
+            while (cur != null) {
+                stack.push(cur);
+                cur = cur.right;
+            }
+            cur = stack.pop();
+            cur.val += curSum;
+            curSum = cur.val;
+            cur = cur.left;
+        }
+
+        return root;
+    }
+}
diff --git a/java/1291-sequential-digits.java b/java/1291-sequential-digits.java
@@ -0,0 +1,20 @@
+class Solution {
+    public List<Integer> sequentialDigits(int low, int high) {
+        List<Integer> res = new ArrayList<>();
+        Queue<Integer> q = new LinkedList<>();
+        for(int i = 1; i < 10; i++)
+            q.add(i);
+
+        while(!q.isEmpty()){
+            int n = q.poll();
+            if(n > high)
+                continue;
+            if(n >= low && n <= high)
+                res.add(n);
+            int ones = n % 10;
+            if(ones < 9)
+                q.add(n * 10 + (ones + 1));
+        }
+        return res;    
+    }
+}
diff --git a/java/1993-operations-on-tree.java b/java/1993-operations-on-tree.java
@@ -0,0 +1,79 @@
+class Solution {
+    private final int[] parent;
+    private final int[] locked;
+    private final Map<Integer, List<Integer>> child;
+
+    public LockingTree(int[] parent) {
+        this.parent = parent;
+        locked = new int[parent.length];
+        child = new HashMap<>();
+
+        for (int i = 0; i < parent.length; i++) {
+            child.putIfAbsent(parent[i], new ArrayList<>());
+            child.putIfAbsent(i, new ArrayList<>());
+            child.get(parent[i]).add(i);
+        }
+    }
+
+    public boolean lock(int num, int user) {
+        if (locked[num] <= 0) {
+            locked[num] = user;
+            return true;
+        }
+
+        return false;
+    }
+
+    public boolean unlock(int num, int user) {
+        if (locked[num] == user) {
+            locked[num] = 0;
+            return true;
+        }
+
+        return false;
+    }
+
+    public boolean upgrade(int num, int user) {
+        if (!noneAncestorsLocked(num)) {
+            return false;
+        }
+
+        int lockedCount = checkDescendantsAndLockIfNeeded(num);
+
+        if (lockedCount > 0) {
+            locked[num] = user;
+        }
+
+        return lockedCount > 0;
+    }
+
+    private boolean noneAncestorsLocked(int num) {
+        while (num != -1) {
+            if (locked[num] != 0) {
+                return false;
+            }
+            num = parent[num];
+        }
+
+        return true;
+    }
+
+    private int checkDescendantsAndLockIfNeeded(int num) {
+        int lockedCount = 0;
+        Deque<Integer> deque = new ArrayDeque<>();
+
+        deque.addFirst(num);
+        while (!deque.isEmpty()) {
+            int n = deque.pollLast();
+            if (locked[n] > 0) {
+                lockedCount++;
+                locked[n] = 0;
+            }
+            for (Integer i : child.get(n)) {
+                deque.addFirst(i);
+            }
+        }
+
+        return lockedCount;
+    }
+}
diff --git a/kotlin/0387-first-unique-character-in-a-string.kt b/kotlin/0387-first-unique-character-in-a-string.kt
@@ -0,0 +1,14 @@
+class Solution {
+    fun firstUniqChar(s: String): Int {
+        var count = IntArray (26)
+        for (c in s)
+            count[c - 'a']++
+
+        for ((i, c) in s.withIndex()) {
+            if (count[c - 'a'] == 1)
+                return i
+        }
+ 
+        return -1
+    }
+}
diff --git a/kotlin/1043-partition-array-for-maximum-sum.kt b/kotlin/1043-partition-array-for-maximum-sum.kt
@@ -0,0 +1,57 @@
+// Dp solution
+class Solution {
+    fun maxSumAfterPartitioning(arr: IntArray, k: Int): Int {
+        val n = arr.size
+        val dp = IntArray (k)
+        dp[0] = arr[0]
+
+        for (i in 1 until n) {
+            var curMax = 0
+            var maxAtI = 0
+            for (j in i downTo (i - k + 1)) {
+                if (j < 0) break
+
+                curMax = maxOf(curMax, arr[j])
+
+                val winLen = i - j + 1
+                val curSum = curMax * winLen
+                val subArrSum = if (j > 0) dp[(j - 1) % k] else dp[k - 1]
+
+                maxAtI = maxOf(maxAtI, curSum + subArrSum)
+            }
+
+            dp[i % k] = maxAtI
+        }
+
+        return dp[(n - 1) % k]
+    }
+}
+
+// recursion + memoization
+class Solution {
+    fun maxSumAfterPartitioning(arr: IntArray, k: Int): Int {
+        val n = arr.size
+        val dp = IntArray (n) { -1 }
+
+        fun dfs(i: Int): Int {
+            if (i == n) return 0
+            if (dp[i] != -1) return dp[i]
+
+            var curMax = 0
+            var res = 0
+            for (j in i until minOf(n, i + k)) {
+                curMax = maxOf(curMax, arr[j])
+                val winLen = j - i + 1
+                res = maxOf(
+                    res,
+                    dfs(j + 1) + curMax * winLen
+                )
+            }
+
+            dp[i] = res
+            return res
+        }
+
+        return dfs(0)
+    }
+}
diff --git a/kotlin/1291-sequential-digits.kt b/kotlin/1291-sequential-digits.kt
@@ -0,0 +1,18 @@
+class Solution {
+    fun sequentialDigits(low: Int, high: Int): List<Int> {
+        var q = mutableListOf(1, 2, 3, 4, 5, 6, 7, 8, 9)
+        var res = mutableListOf<Int>()
+
+        while (q.isNotEmpty()) {
+            var n = q.removeFirst()
+
+            if (n > high) continue
+            if (n >= low) res.add(n)
+
+            val d = n % 10
+            if (d < 9) q.add(n * 10 + (d + 1))
+        }
+
+        return res
+    }
+}
