【一起学数据结构与算法】深度学习栈_深度学习技术栈，2024年最新分布式架构演进+相关笔记参考

    s1.push(2);
    s1.push(3);
    s1.push(4);
    System.out.println(s1);

![在这里插入图片描述](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/9b92b7ca29b149a6b83302402ec482d3~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=pn9425HXBFZMu%2BA3RqQkhvG890s%3D)


### 2.2 判空 - empty()

    Stack<Integer> s1 = new Stack<>();
    s1.push(1);
    s1.push(2);
    s1.push(3);
    s1.push(4);
    System.out.println(s1.empty());

![在这里插入图片描述](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/c8b1f6a9b6d047d1add67e865047df79~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=eNJvJ1vdktVlR1epdiQsABXN%2FNQ%3D)


### 2.3 出栈 - pop()

  Stack<Integer> s1 = new Stack<>();
  s1.push(1);
  s1.push(2);
  s1.push(3);
  s1.push(4);
  System.out.println(s1);
  s1.pop();
  System.out.println(s1);

![在这里插入图片描述](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/736fe44ef2e34a428117f1c62ca1537a~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=UlTiNiu3utf8JXj7c9z1nyQLZ84%3D)


### 2.4 获取栈顶元素 - peek()

    Stack<Integer> s1 = new Stack<>();
    s1.push(1);
    s1.push(2);
    s1.push(3);
    s1.push(4);
    System.out.println(s1);
    s1.peek();
    System.out.println(s1);
    System.out.println(s1.peek());

![在这里插入图片描述](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/8beed44c1a0d4da98e4150cf8423f2a4~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=fLsc2219RJ9mqPlutg7i0gUAwSk%3D)


### 2.5 获取栈中有效元素个数 - size()

    Stack<Integer> s1 = new Stack<>();
    s1.push(1);
    s1.push(2);
    s1.push(3);
    s1.push(4);
    System.out.println(s1.size());

![在这里插入图片描述](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/a878defbc99e4de685370a337b997744~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=98f2WxeyqJWzXhZeuQ24MqJycVM%3D)


## 三、栈的模拟实现


### 3.1 push

public boolean isFull() {
    return this.usedSize == this.elem.length;
}

public void push(int val) {
    if (isFull()) {
        //扩容
        this.elem = Arrays.copyOf(this.elem,2\*this.usedSize);
    }
    this.elem[this.usedSize] = val;
    this.usedSize++;
}

### 3.2 isEmpty

public boolean isEmpty() {
    return this.usedSize == 0;
}

### 3.3 pop

public int pop() {
    if (isEmpty()) {
        throw new RuntimeException("栈为空");
    }
    int oldVal = this.elem[usedSize-1];
    this.usedSize--;
    return oldVal;
}

### 3.4 peek

public int peek() {
    if (isEmpty()) {
        throw new RuntimeException("栈为空");
    }
    return this.elem[usedSize-1];
}

### 3.5 MyStack.java

import java.lang.reflect.Array; import java.util.Arrays;

@SuppressWarnings({"all"}) public class MyStack { public int[] elem; public int usedSize;

public MyStack() {
    this.elem = new int[5];
}

public void push(int val) {
    if (isFull()) {
        //扩容
        this.elem = Arrays.copyOf(this.elem,2\*this.usedSize);
    }
    this.elem[this.usedSize] = val;
    this.usedSize++;
}

public boolean isFull() {
    return this.usedSize == this.elem.length;
}

public int pop() {
    if (isEmpty()) {
        throw new RuntimeException("栈为空");
    }
    int oldVal = this.elem[usedSize-1];
    this.usedSize--;
    return oldVal;
}

public int peek() {
    if (isEmpty()) {
        throw new RuntimeException("栈为空");
    }
    return this.elem[usedSize-1];
}

public boolean isEmpty() {
    return this.usedSize == 0;
}

}

## 四、经典题


### 4.1 有效的括号


![在这里插入图片描述](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/72e72d86059644fca0e630220fc9856f~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=P%2BtUHIvds9w6SLvPExxU%2BAOKo%2F4%3D)

class Solution { public boolean isValid(String s) { Stack stack = new Stack<>();

    for (int i = 0; i < s.length(); i++) {
        char ch = s.charAt(i);
        if (ch == '(' || ch == '[' || ch == '{') {
            //如果是左括号 直接入栈
            stack.push(ch);
        } else {
            //遇到了右括号
            if (stack.empty()) {
                System.out.println("右括号多");
                return false;
            } 
            char top = stack.peek();//哪个左括号
            if (top == '(' && ch ==')' || top == '[' && ch ==']' || top == '{' && ch =='}') {
                stack.pop();
            } else {
                System.out.println("左右括号不匹配");
                return false;
            }
        }
    }
    if (!stack.empty()) {
        System.out.println("左括号多");
        return false;
    }
    return true;
}

}

### 4.2 逆波兰表达式求值


![img](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/db0428703a624fcea247ae5808df2789~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=2e%2B95oaArg67S7gEQVe2DCbPETI%3D)
![img](https://p3-xtjj-sign.byteimg.com/tos-cn-i-73owjymdk6/4f304501fe2843baa4a9a546330d8cf4~tplv-73owjymdk6-jj-mark-v1:0:0:0:0:5o6Y6YeR5oqA5pyv56S-5Yy6IEAg5py65Zmo5a2m5Lmg5LmL5b-DQUk=:q75.awebp?rk3s=f64ab15b&x-expires=1773671591&x-signature=z2z6yYP3mtF%2BeHahfx7cBQdnozI%3D)

**网上学习资料一大堆，但如果学到的知识不成体系，遇到问题时只是浅尝辄止，不再深入研究，那么很难做到真正的技术提升。**

**[需要这份系统化资料的朋友，可以戳这里获取](https://gitee.com/vip204888)**


**一个人可以走的很快，但一群人才能走的更远！不论你是正从事IT行业的老鸟或是对IT行业感兴趣的新人，都欢迎加入我们的的圈子（技术交流、学习资源、职场吐槽、大厂内推、面试辅导），让我们一起学习成长！**