# POJ3040 Allowance

## Description

As a reward for record milk production, Farmer John has decided to start paying Bessie the cow a small weekly allowance. FJ has a set of coins in N (1 <= N <= 20) different denominations, where each denomination of coin evenly divides the next-larger denomination (e.g., 1 cent coins, 5 cent coins, 10 cent coins, and 50 cent coins).Using the given set of coins, he would like to pay Bessie at least some given amount of money C (1 <= C <= 100,000,000) every week.Please help him ompute the maximum number of weeks he can pay Bessie.

## Input

* Line 1: Two space-separated integers: N and C

* Lines 2..N+1: Each line corresponds to a denomination of coin and contains two integers: the value V (1 <= V <= 100,000,000) of the denomination, and the number of coins B (1 <= B <= 1,000,000) of this denomation in Farmer John's possession.

## Output

* Line 1: A single integer that is the number of weeks Farmer John can pay Bessie at least C allowance

## Hint

INPUT DETAILS: FJ would like to pay Bessie 6 cents per week. He has 100 1-cent coins,120 5-cent coins, and 1 10-cent coin.

OUTPUT DETAILS: FJ can overpay Bessie with the one 10-cent coin for 1 week, then pay Bessie two 5-cent coins for 10 weeks and then pay Bessie one 1-cent coin and one 5-cent coin for 100 weeks.

## Analysis

1. 题意就是你有很多张面额不同的纸币，你每个星期要给奶牛至少c元，问你用现在的钱最多给奶牛多少周。
2. 首先，将大于等于c的面额的钱直接每个星期给奶牛一张，将面额大于等于c的钱去除。
3. 然后从大到小开始选择，要选择的金额尽可能的接近c，如果刚好能够凑足c就作为当前的一种方案，如果不能凑足c那就再从小的开始选，要选出一种的总额不少于c但尽量接近c作为当前的方案。
4. 然后计算如果按照如此方案最多可以给奶牛多少周，然后按照相同的方法再选方案，一直选到选择的金额不能凑足c为止。
5. .https://blog.csdn.net/yopilipala/article/details/79607185
# POJ