1/* 2 * Copyright (c) 2024-2025 Huawei Device Co., Ltd. 3 * Licensed under the Apache License, Version 2.0 (the "License"); 4 * you may not use this file except in compliance with the License. 5 * You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software 10 * distributed under the License is distributed on an "AS IS" BASIS, 11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 * See the License for the specific language governing permissions and 13 * limitations under the License. 14 */ 15 16interface MyStack<Item> { 17 getTop() : Item|null; 18 pop() : Item|null; 19 push(item : Item) : void; 20 isEmpty() : boolean; 21 size() : int; 22} 23 24class MyArrayStack<Item> implements MyStack<Item> { 25 26 private container : (Item | undefined)[]; 27 private top : int = -1; 28 private readonly DEFAULT_SIZE : int = 100; 29 30 constructor() { 31 this.container = new (Item | undefined)[this.DEFAULT_SIZE]; 32 this.top = -1; 33 } 34 35 constructor(size: int) { 36 this.container = new (Item | undefined)[size]; 37 } 38 39 override getTop() : Item|null { 40 if (this.top == -1) { 41 return null; 42 } 43 return this.container[this.top]!; 44 } 45 46 override pop() : Item|null { 47 if (this.top == -1) { 48 return null; 49 } 50 return this.container[this.top--]!; 51 } 52 53 override push(item : Item) : void { 54 this.container[++this.top] = item; 55 } 56 57 override isEmpty() : boolean { 58 return (this.top == -1); 59 } 60 61 override size() : int { 62 return (this.top + 1); 63 } 64} 65 66function main() : void { 67 let stack1 : MyArrayStack<Int>; 68 stack1 = new MyArrayStack<Int>(); 69 assertEQ(stack1.isEmpty(), true) 70 assertEQ(stack1.size(), 0) 71 72 stack1.push(new Int(10)); 73 assertEQ(stack1.isEmpty(), false) 74 assertEQ(stack1.size(), 1) 75 assertEQ((stack1.getTop() as Int), 10) 76 77 stack1.push(new Int(20)); 78 stack1.push(new Int(30)); 79 assertEQ(stack1.isEmpty(), false) 80 assertEQ(stack1.size(), 3) 81 assertEQ((stack1.getTop() as Int), 30) 82 83 assertEQ((stack1.pop() as Int), 30) 84 assertEQ(stack1.size(), 2) 85 assertEQ((stack1.pop() as Int), 20) 86 assertEQ(stack1.size(), 1) 87 assertEQ((stack1.pop() as Int), 10) 88 assertEQ(stack1.size(), 0) 89 assertEQ(stack1.isEmpty(), true) 90 91 assertEQ(stack1.getTop(), null) 92 assertEQ(stack1.pop(), null) 93 assertEQ(stack1.size(), 0) 94 assertEQ(stack1.isEmpty(), true) 95 96} 97