codeforces 349A

題目並不難，不過要整理好思路 （依次判斷25的個數、50的個數），依然需要一個true 和false的判斷變量。

n = int(raw_input())
money = map(int,raw_input().split())

price_25 = 0
price_50 = 0
price_100 = 0

result = True

for item in money:
    if item == 25:
        price_25 += 1

    elif item == 50:
        price_50 += 1
        if price_25 >= 1:
            price_25 -= 1
        else:
            result = False
            break

    elif item == 100:
        if price_50 >=1 and price_25 >=1:
            price_50 -= 1
            price_25 -= 1
        elif price_25 >=3:
            price_25 -=3
        else:
            result = False
            break

if result == False:
    print "NO"
else:
    print "YES"