golang 栈操作

Posted 2020-09-18 学无止境，每天进步一小步

Monk‘s Love for Food

 

Our monk loves food. Hence,he took up position of a manager at Sagar,a restaurant that serves people with delicious food packages. It is a very famous place and people are always queuing up to have one of those packages. Each package has a cost associated with it. The packages are kept as a pile. The job of a manager is very difficult. He needs to handle two types of queries:

1) Customer Query:
When a customer demands a package, the food package on the top of the pile is given and the customer is charged according to the cost of the package. This reduces the height of the pile by 1. 
In case the pile is empty, the customer goes away empty-handed.

2) Chef Query:
The chef prepares a food package and adds it on top of the pile. And reports the cost of the package to the Manager.
Help him manage the process.

Input:
First line contains an integer Q, the number of queries. Q lines follow.
A Type-1 ( Customer) Query, is indicated by a single integer 1 in the line.
A Type-2 ( Chef) Query, is indicated by two space separated integers 2 and C (cost of the package prepared) .

Output:
For each Type-1 Query, output the price that customer has to pay i.e. cost of the package given to the customer in a new line. If the pile is empty, print "No Food" (without the quotes).

Constraints:
1 ≤ Q ≤ 10⁵
1 ≤ C ≤ 10⁷

用到了slice的两个基本方法  stack = stack[0:stackLength-1] 就是将最后的一个元素删除，slice中下标用的其实是相当[0,stackLength-1} 就是从前标开始，包括前标到后标，但是不包括后标，下来就是往slice中添加元素。

package main

import "fmt"


var stack []int

func main() {
	var inputCount int
	fmt.Scanln(&inputCount)
	
	stack = make([]int,0,0)
	
	var flag,value int
	var stackLength int
	for i:=0;i<inputCount;i++{
	    fmt.Scanln(&flag,&value)
	    stackLength = len(stack)
	    if(flag ==1){
	        if(stackLength == 0){
	            fmt.Println("No Food")
	        }else{
	           fmt.Println(stack[stackLength-1])
	           stack = stack[0:stackLength-1]
	        }
	    }else{
	       stack = append(stack,value) 
	    }
	}
}