TOJ 2838.The Eating Puzzle

题目链接：http://acm.tju.edu.cn/toj/showp2838.html

2838.   The Eating Puzzle
Time Limit: 1.0 Seconds   Memory Limit: 65536K
Total Runs: 1489   Accepted Runs: 776    Multiple test files

Bessie is on a diet where she can eat no more than C (10 ≤ C ≤ 35,000) calories per day. Farmer John is teasing her by putting out B (1 ≤ B ≤ 21) buckets of feed, each with some (potentially
non-unique) number of calories (range: 1..35,000). Bessie has no self-control: once she starts on a feed bucket, she consumes all of it.
Bessie is not so good at combinatorics. Determine the optimal combination of feed buckets that gives Bessie as many calories without exceeding the limit C.
As an example, consider a limit of 40 calories and 6 buckets with 7, 13, 17, 19, 29, and 31 calories. Bessie could eat 7 + 31 = 38 calories but could eat even more by consuming three buckets: 7 + 13 + 19
= 39 calories. She can find no better combination.

Input

* Line 1: Two space-separated integers: C and B
* Line 2: B space-separated integers that respectively name the number of calories in bucket 1, 2, etc.

Output

* Line 1: A single line with a single integer that is largest number of calories Bessie can consume and still stay on her diet.

Sample Input

40 6
7 13 17 19 29 31

Sample Output

39

Source: USACO
2006 December Competition
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01背包，过之：

#include <stdio.h>
#include <string.h>
#include <algorithm>
int dp[35001];
int a[22];
int main(){
int num,n;
while(~scanf("%d%d",&num,&n)){
for(int i=0;i<n;i++)
scanf("%d",&a[i]);
memset(dp,0,sizeof(dp));
for(int i=0;i<n;i++)
for(int j=num;j>=a[i];j--)
dp[j]=std::max(dp[j],dp[j-a[i]]+a[i]);
printf("%d\n",dp[num]);
}
}