A. Cinema Line

time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

The new "Die Hard" movie has just been released! There are n people at the cinema box office standing in a huge line. Each of them has a single 100, 50 or 25 ruble bill. A "Die Hard" ticket costs 25 rubles. Can the booking clerk sell a ticket to each person and give the change if he initially has no money and sells the tickets strictly in the order people follow in the line?

Input

The first line contains integer n (1 ≤ n ≤ 105) — the number of people in the line. The next line contains n integers, each of them equals 25, 50 or 100 — the values of the bills the people have. The numbers are given in the order from the beginning of the line (at the box office) to the end of the line.

Output

Print "YES" (without the quotes) if the booking clerk can sell a ticket to each person and give the change. Otherwise print "NO".

Examples
input
Copy
4
25 25 50 50
output
Copy
YES
input
Copy
2
25 100
output
Copy
NO
input
Copy
4
50 50 25 25
output
Copy
NO


#include<iostream>
#include<string.h>
using namespace std;
int main()
{
    int n,a[100005];
    cin>>n;
    for(int i=0;i<n;i++)
    {
        cin>>a[i];
    }
    int t1=0,t2=0,flag=1;
    for(int i=0;i<n;i++)
    {
        if(a[i]==25)
        {
            t1++;
            continue;
        }
        if(a[i]==50)
        {
            if(t1>=1)
            {
                t2++;
                t1--;
                continue;
            }
            else
            {
                flag=0;
                break;
            }
        }
        if(a[i]==100)
        {
            if(t1>=1&&t2>=1)
            {
                t1--;
                t2--;
                continue;
            }
            if(t1>=3)
            {
                t1=t1-3;
                continue;
            }

            else
            {
                flag=0;
                break;
            }
        }

    }
    if(flag==1)
        cout<<"YES"<<endl;
    else
        cout<<"NO"<<endl;
    return 0;
}

 

posted @ 2018-09-25 21:22  知道了呀~  阅读(311)  评论(0编辑  收藏  举报