diff --git a/typescript/1046-Last-Stone-Weight.ts b/typescript/1046-Last-Stone-Weight.ts new file mode 100644 index 000000000..b91fa8b56 --- /dev/null +++ b/typescript/1046-Last-Stone-Weight.ts @@ -0,0 +1,78 @@ +class MaxHeap { + heap: number[] + constructor(array: number[]) { + this.heap = this.buildHeap(array) + } + + buildHeap(array: number[]) { + let parentIdx = Math.floor((array.length - 2) / 2) + for (let i = parentIdx; i >= 0; i--) { + this.siftDown(i, array.length - 1, array) + } + return array + } + + siftDown(idx: number, endIdx: number, heap: number[]) { + let childOneIdx = 2 * idx + 1 + + while (childOneIdx <= endIdx) { + let childTwoIdx = 2 * idx + 2 <= endIdx ? 2 * idx + 2 : -1 + let swapIdx + if (childTwoIdx !== -1 && heap[childOneIdx] < heap[childTwoIdx]) { + swapIdx = childTwoIdx + } else swapIdx = childOneIdx + if (heap[swapIdx] > heap[idx]) { + this.swap(swapIdx, idx, heap) + idx = swapIdx + childOneIdx = 2 * idx + 1 + } else return + } + } + + siftUp(idx: number, heap: number[]) { + let parentIdx = Math.floor((idx - 1) / 2) + while (heap[parentIdx] < heap[idx] && idx > 0) { + this.swap(parentIdx, idx, heap) + idx = parentIdx + parentIdx = Math.floor((idx - 1) / 2) + } + } + + peek() { + return this.heap[0] + } + + remove() { + this.swap(this.heap.length - 1, 0, this.heap) + const removeValue = this.heap.pop() + this.siftDown(0, this.heap.length - 1, this.heap) + return removeValue + } + + size() { + return this.heap.length + } + + insert(value: number) { + this.heap.push(value) + this.siftUp(this.heap.length - 1, this.heap) + } + swap(i: number, j: number, arr: number[]) { + let ele = arr[i] + arr[i] = arr[j] + arr[j] = ele + } +} + +function lastStoneWeight(stones: number[]): number { + const heap = new MaxHeap(stones) + + while (heap.size() > 1) { + const stone1 = heap.remove() + const stone2 = heap.remove() + + heap.insert(stone1 - stone2) + } + + return heap.peek() +} diff --git a/typescript/23-Merge-k-Sorted-Lists.ts b/typescript/23-Merge-k-Sorted-Lists.ts new file mode 100644 index 000000000..63891c8b6 --- /dev/null +++ b/typescript/23-Merge-k-Sorted-Lists.ts @@ -0,0 +1,52 @@ +/** + * Definition for singly-linked list. + * class ListNode { + * val: number + * next: ListNode | null + * constructor(val?: number, next?: ListNode | null) { + * this.val = (val===undefined ? 0 : val) + * this.next = (next===undefined ? null : next) + * } + * } + */ + +function mergeKLists(lists: Array): ListNode | null { + if (lists.length === 0) return null + + while (lists.length > 1) { + let resultList = [] + + for (let i = 0; i < lists.length; i += 2) { + let list1 = lists[i] + let list2 + if (i + 1 > lists.length) list2 = null + else list2 = lists[i + 1] + resultList.push(mergeList(list1, list2)) + } + + lists = resultList + } + return lists[0] || null +} + +function mergeList( + list1: ListNode | null, + list2: ListNode | null +): ListNode | null { + let dummyNode: ListNode | null = new ListNode() + let tail = dummyNode + + while (list1 && list2) { + if (list1.val < list2.val) { + tail.next = list1 + list1 = list1.next + } else { + tail.next = list2 + list2 = list2.next + } + tail = tail.next + } + tail.next = list1 || list2 + + return dummyNode.next +} pFad - Phonifier reborn

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