Go-两个栈实现一个类似队列操作

绝地灬酷狼 2022-09-09 13:00 91阅读 0赞

栈的实现可以参考之前的博文。

本文代码片段如下：

/*
     *                    .::::.
     *                  .::::::::.
     *                 :::::::::::
     *             ..:::::::::::'
     *           '::::::::::::'
     *             .::::::::::
     *        '::::::::::::::..
     *             ..::::::::::::.		Utils:两个栈实现一个类似队列操作
     *           ``::::::::::::::::		Author:崔金朋
     *            ::::``:::::::::'        .:::.
     *           ::::'   ':::::'       .::::::::.
     *         .::::'      ::::     .:::::::'::::.
     *        .:::'       :::::  .:::::::::' ':::::.
     *       .::'        :::::.:::::::::'      ':::::.
     *      .::'         ::::::::::::::'         ``::::.
     *  ...:::           ::::::::::::'              ``::.
     * ```` ':.          ':::::::::'                  ::::..
     *  		           '.:::::'          			':'````..
     */
    
    package main
    
    import (
    	"errors"
    )
    
    type List struct {
    	stackPush []interface{}
    	stackPop  []interface{}
    }
    
    // 查验队列是否为空
    func (l *List) IsEmpty() bool {
    	return len(l.stackPop) == 0
    }
    
    // 向队列中添加一个元素
    func (l *List) Add(item interface{}) (bool, error) {
    	if item == nil {
    		return false, errors.New("数据不能为空")
    	}
    
    	l.stackPush = append(l.stackPush, item)
    	return true, nil
    }
    
    // 向队列尾部添加一个元素
    func (l *List) AddLast(item interface{}) (bool, error) {
    	if item == nil {
    		return false, errors.New("数据不能为空")
    	}
    
    	pushLen := len(l.stackPush)
    	popLen := len(l.stackPop)
    	if pushLen == 0 && popLen == 0 {
    		l.stackPop = append(l.stackPop, item)
    	} else if popLen > 0 && pushLen == 0 {
    		if popLen == 1 {
    			l.stackPop = append(l.stackPop, item)
    			l.stackPop[1] = l.stackPop[0]
    			l.stackPop[0] = item
    		} else {
    			l.stackPop = append(l.stackPop[len(l.stackPop)-1:], l.stackPop[0:]...)
    			l.stackPop[0] = item
    		}
    	} else if popLen == 0 && pushLen > 0 {
    		l.stackPush = append(l.stackPush[len(l.stackPush)-1:], l.stackPush[0:]...)
    		l.stackPush[0] = item
    		for key := range l.stackPush {
    			l.stackPop = append(l.stackPop, l.stackPush[pushLen-key-1])
    		}
    
    		l.stackPush = []interface{}{}
    	} else {
    		for key := range l.stackPush {
    			l.stackPop = append(l.stackPop, l.stackPush[pushLen-key-1])
    		}
    
    		l.stackPush = []interface{}{}
    	}
    
    	return true, nil
    }
    
    // 将首个元素从队列中弹出，如果队列是空的，就返回nil
    func (l *List) Poll() (interface{}, error) {
    	pushLen := len(l.stackPush)
    	popLen := len(l.stackPop)
    	if popLen == 0 && pushLen == 0 {
    		return 0, errors.New("队列为空")
    	}
    
    	if popLen == 0 && pushLen > 0 {
    		for key := range l.stackPush {
    			l.stackPop = append(l.stackPop, l.stackPush[pushLen-key-1])
    		}
    
    		l.stackPush = []interface{}{}
    	}
    
    	var item interface{}
    	length := len(l.stackPop)
    	if length == 0 {
    		return item, errors.New("数据不存在")
    	} else if length == 1 {
    		item = l.stackPop[0]
    		l.stackPop = []interface{}{}
    	} else {
    		item = l.stackPop[length-1]
    		l.stackPop = l.stackPop[0 : length-1]
    	}
    
    	return item, nil
    }
    
    // 将最后一个元素从队列中弹出，如果队列是空的，就返回nil
    func (l *List) PollLast() (interface{}, error) {
    	pushLen := len(l.stackPush)
    	popLen := len(l.stackPop)
    	if popLen == 0 && pushLen == 0 {
    		return 0, errors.New("队列为空")
    	}
    
    	if popLen == 0 && pushLen > 0 {
    		for key := range l.stackPush {
    			l.stackPop = append(l.stackPop, l.stackPush[pushLen-key-1])
    		}
    
    		l.stackPush = []interface{}{}
    	}
    
    	var item interface{}
    	length := len(l.stackPop)
    	if length == 0 {
    		return item, errors.New("数据不存在")
    	} else if length == 1 {
    		item = l.stackPop[0]
    		l.stackPop = []interface{}{}
    	} else {
    		item = l.stackPop[0]
    		l.stackPop = l.stackPop[1 : length-1]
    	}
    
    	return item, nil
    }
    
    // 查看首个元素，不会移除首个元素，如果队列是空的就返回nil
    func (l *List) Peek() (interface{}, error) {
    	pushLen := len(l.stackPush)
    	popLen := len(l.stackPop)
    	if popLen == 0 && pushLen == 0 {
    		return 0, errors.New("队列为空")
    	}
    
    	if popLen == 0 && pushLen > 0 {
    		for key := range l.stackPush {
    			l.stackPop = append(l.stackPop, l.stackPush[pushLen-key-1])
    		}
    
    		l.stackPush = []interface{}{}
    	}
    
    	var item interface{}
    	length := len(l.stackPop)
    	if length == 0 {
    		return item, errors.New("数据不存在")
    	} else if length == 1 {
    		item = l.stackPop[0]
    	} else {
    		item = l.stackPop[length-1]
    	}
    
    	return item, nil
    }
    
    // 查看最后一个元素，不会移除最后一个元素，如果队列是空的就返回nil
    func (l *List) PeekLast() int {
    	pushLen := len(l.stackPush)
    	popLen := len(l.stackPop)
    	if popLen == 0 && pushLen == 0 {
    		return 0
    	}
    
    	if popLen == 0 && pushLen > 0 {
    		for key := range l.stackPush {
    			l.stackPop = append(l.stackPop, l.stackPush[pushLen-key-1])
    		}
    
    		l.stackPush = []interface{}{}
    	}
    
    	if len(l.stackPop) == 0 {
    		return 0
    	}
    
    	return l.stackPop[0].(int)
    }
    
    // 查看最后一个元素，不会移除最后一个元素，如果队列是空的就返回nil
    func (l *List) PeekFirst() int {
    	pushLen := len(l.stackPush)
    	popLen := len(l.stackPop)
    	if popLen == 0 && pushLen == 0 {
    		return 0
    	}
    
    	if popLen == 0 && pushLen > 0 {
    		for key := range l.stackPush {
    			l.stackPop = append(l.stackPop, l.stackPush[pushLen-key-1])
    		}
    
    		l.stackPush = []interface{}{}
    	}
    
    	if len(l.stackPop) == 0 {
    		return 0
    	}
    
    	return l.stackPop[len(l.stackPop)-1].(int)
    }