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js 实现栈

2026-04-06 22:34:52JavaScript

使用数组实现栈

在JavaScript中，可以通过数组来模拟栈的行为。数组的push和pop方法天然适合栈的后进先出（LIFO）特性。

js 实现栈

class Stack {
  constructor() {
    this.items = [];
  }

  push(element) {
    this.items.push(element);
  }

  pop() {
    if (this.isEmpty()) {
      return "Underflow";
    }
    return this.items.pop();
  }

  peek() {
    return this.items[this.items.length - 1];
  }

  isEmpty() {
    return this.items.length === 0;
  }

  size() {
    return this.items.length;
  }

  clear() {
    this.items = [];
  }

  print() {
    console.log(this.items.toString());
  }
}

使用对象实现栈

对于需要更高性能的场景，可以使用对象来存储栈元素，避免数组的索引调整开销。

js 实现栈

class Stack {
  constructor() {
    this.items = {};
    this.count = 0;
  }

  push(element) {
    this.items[this.count] = element;
    this.count++;
  }

  pop() {
    if (this.isEmpty()) {
      return "Underflow";
    }
    this.count--;
    const result = this.items[this.count];
    delete this.items[this.count];
    return result;
  }

  peek() {
    return this.items[this.count - 1];
  }

  isEmpty() {
    return this.count === 0;
  }

  size() {
    return this.count;
  }

  clear() {
    this.items = {};
    this.count = 0;
  }

  print() {
    console.log(Object.values(this.items).toString());
  }
}

栈的应用示例

栈的典型应用包括括号匹配、表达式求值、函数调用栈等。以下是一个括号匹配的示例：

function isBalanced(expression) {
  const stack = new Stack();
  const map = {
    '(': ')',
    '[': ']',
    '{': '}'
  };

  for (let char of expression) {
    if (char in map) {
      stack.push(char);
    } else {
      if (stack.isEmpty()) return false;
      const last = stack.pop();
      if (map[last] !== char) return false;
    }
  }

  return stack.isEmpty();
}

console.log(isBalanced("{[()]}")); // true
console.log(isBalanced("{[(]}")); // false