[sooooo-an] WEEK 04 Solutions

combination-sum/sooooo-an.ts

@@ -0,0 +1,23 @@
+function combinationSum(candidates: number[], target: number): number[][] {
+  const result: number[][] = [];
+
+  const dfs = (start: number, path: number[], sum: number) => {
+    if (sum === target) {
+      result.push([...path]);
+      return;
+    }
+
+    if (sum > target) {
+      return;
+    }
+
+    for (let i = start; i < candidates.length; i++) {
+      path.push(candidates[i]);
+      dfs(i, path, sum + candidates[i]);
+      path.pop();
+    }
+  };
+
+  dfs(0, [], 0);
+  return result;
+}

find-minimum-in-rotated-sorted-array/sooooo-an.ts

@@ -0,0 +1,15 @@
+function findMin(nums: number[]): number {
+  let left = 0,
+    right = nums.length - 1;
+
+  while (left < right) {
+    const mid = left + Math.floor((right - left) / 2);
+    if (nums[mid] > nums[right]) {
+      left = mid + 1;
+    } else {
+      right = mid;
+    }
+  }
+
+  return nums[left];
+}

maximum-depth-of-binary-tree/sooooo-an.ts

@@ -0,0 +1,6 @@
+function maxDepth(root: TreeNode | null): number {
+  if (!root) return 0;
+  const left = maxDepth(root.left);
+  const right = maxDepth(root.right);
+  return Math.max(left, right) + 1;
+}

merge-two-sorted-lists/sooooo-an.ts

@@ -0,0 +1,22 @@
+function mergeTwoLists(
+  list1: ListNode | null,
+  list2: ListNode | null
+): ListNode | null {
+  const result = new ListNode();
+  let tail = result;
+
+  while (list1 !== null && list2 !== null) {
+    if (list1.val <= list2.val) {
+      tail.next = list1;
+      list1 = list1.next;
+    } else {
+      tail.next = list2;
+      list2 = list2.next;
+    }
+    tail = tail.next;
+  }
+
+  tail.next = list1 !== null ? list1 : list2;
+
+  return result.next;
+}