标签：pre inpu OLE Plan code ack bool receive 组合
At a lemonade stand, each lemonade costs $5.
Customers are standing in a queue to buy from you, and order one at a time (in the order specified by bills).
Each customer will only buy one lemonade and pay with either a $5, $10, or $20 bill. You must provide the correct change to each customer, so that the net transaction is that the customer pays $5.
Note that you don‘t have any change in hand at first.
Return true if and only if you can provide every customer with correct change.
Example 1:
Input: [5,5,5,10,20] Output: true Explanation: From the first 3 customers, we collect three $5 bills in order. From the fourth customer, we collect a $10 bill and give back a $5. From the fifth customer, we give a $10 bill and a $5 bill. Since all customers got correct change, we output true.
Example 2:
Input: [5,5,10] Output: true
Example 3:
Input: [10,10] Output: false
Example 4:
Input: [5,5,10,10,20] Output: false Explanation: From the first two customers in order, we collect two $5 bills. For the next two customers in order, we collect a $10 bill and give back a $5 bill. For the last customer, we can‘t give change of $15 back because we only have two $10 bills. Since not every customer received correct change, the answer is false.
Note:
0 <= bills.length <= 10000bills[i] will be either 5, 10, or 20.柠檬水找零。题意是你在卖柠檬水，5美金一杯。顾客只会以5，10和20美金面值的钞票来跟你买。给你一堆客人的钞票面值，请问你是否有合适的，足够的钱找零。
思路是贪心。这里贪的是如果要找15美金，就一定要先尝试用10 + 5的组合而不是3个5的组合找钱。
时间O(n)
空间O(1)
Java实现
1 class Solution { 2 public boolean lemonadeChange(int[] bills) { 3 int five = 0; 4 int ten = 0; 5 for (int bill : bills) { 6 if (bill == 5) { 7 five++; 8 } else if (bill == 10) { 9 if (five == 0) { 10 return false; 11 } 12 five--; 13 ten++; 14 } else { 15 if (five > 0 && ten > 0) { 16 five--; 17 ten--; 18 } else if (five >= 3) { 19 five -= 3; 20 } else { 21 return false; 22 } 23 } 24 } 25 return true; 26 } 27 }
[LeetCode] 860. Lemonade Change
标签：pre inpu OLE Plan code ack bool receive 组合
原文地址：https://www.cnblogs.com/cnoodle/p/13070225.html
