Merge pull request #2191 from prgmr99/main

[prgmr99] WEEK 04 solutions

Author: prgmr99

coin-change/prgmr99.js

@@ -0,0 +1,20 @@
+/**
+ * @param {number[]} coins
+ * @param {number} amount
+ * @return {number}
+ */
+var coinChange = function (coins, amount) {
+  const dp = new Array(amount + 1).fill(amount + 1);
+
+  dp[0] = 0;
+
+  for (let i = 1; i <= amount; i++) {
+    for (let coin of coins) {
+      if (i >= coin) {
+        dp[i] = Math.min(dp[i], dp[i - coin] + 1);
+      }
+    }
+  }
+
+  return dp[amount] > amount ? -1 : dp[amount];
+};

find-minimum-in-rotated-sorted-array/prgmr99.js

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+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var findMin = function (nums) {
+  const length = nums.length;
+
+  let left = 0;
+  let right = length - 1;
+  let result = Infinity;
+
+  while (left <= right) {
+    let mid = Math.floor((left + right) / 2);
+
+    if (nums[mid] < nums[left]) {
+      result = Math.min(result, nums[mid]);
+      right = mid - 1;
+    } else {
+      result = Math.min(result, nums[left]);
+      left = mid + 1;
+    }
+  }
+
+  return result;
+};

maximum-depth-of-binary-tree/prgmr99.js

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+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @return {number}
+ */
+var maxDepth = function (root) {
+  if (!root) return 0;
+
+  const leftDepth = maxDepth(root.left);
+  const rightDepth = maxDepth(root.right);
+
+  return Math.max(leftDepth, rightDepth) + 1;
+};

merge-two-sorted-lists/prgmr99.js

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+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode} list1
+ * @param {ListNode} list2
+ * @return {ListNode}
+ */
+var mergeTwoLists = function (list1, list2) {
+  let dummy = new ListNode(0);
+  let currentNode = dummy;
+
+  while (list1 && list2) {
+    if (list1.val < list2.val) {
+      currentNode.next = list1;
+      list1 = list1.next;
+    } else {
+      currentNode.next = list2;
+      list2 = list2.next;
+    }
+    currentNode = currentNode.next;
+  }
+
+  if (list1) currentNode.next = list1;
+  if (list2) currentNode.next = list2;
+
+  return dummy.next;
+};

word-search/prgmr99.js

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+/**
+ * @param {character[][]} board
+ * @param {string} word
+ * @return {boolean}
+ */
+var exist = function (board, word) {
+  const m = board.length;
+  const n = board[0].length;
+
+  const dfs = (row, col, index) => {
+    if (index === word.length) return true;
+
+    if (
+      row < 0 ||
+      row >= m ||
+      col < 0 ||
+      col >= n ||
+      board[row][col] !== word[index]
+    ) {
+      return false;
+    }
+
+    const temp = board[row][col];
+    board[row][col] = "#";
+
+    const found =
+      dfs(row + 1, col, index + 1) ||
+      dfs(row - 1, col, index + 1) ||
+      dfs(row, col + 1, index + 1) ||
+      dfs(row, col - 1, index + 1);
+
+    board[row][col] = temp;
+
+    return found;
+  };
+
+  for (let r = 0; r < m; r++) {
+    for (let c = 0; c < n; c++) {
+      if (board[r][c] === word[0] && dfs(r, c, 1)) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+};