Cinema Line

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 single100, 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 or100 — 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".

Sample test(s)

input

425 25 50 50

output

YES

input

225 100

output

NO

input

450 50 25 25

output

NO

思路：模拟+贪心，判断当前能不能够买就行了

AC代码如下：

#include <iostream>#include <cstring>using namespace std;int main(){    int n;    int sum=0;    int tmp;    cin>>n;    int i;    int a50,a25,a100;    a25=a50=a100=0;    bool ok=true;   for(int i=0;i<n;i++){        cin>>tmp;        if(tmp==25) a25++;        else if(tmp==50){            if(a25>0){                a25--,a50++;            }            else {                ok=false;                 break;            }        }        else {            if(a25>0 && a50>0){                a25--;a50--;            }else if(a25>=3){                a25-=3;            }            else {                ok=false;                break;            }        }   }   if(ok) cout<<"YES"<<endl;    else cout<<"NO"<<endl;    return 0;}