大意： 面值为1分，2分，3分的硬币各有a,b,c枚，求不能用这些硬币表示的最小值。
分析：硬币能够表示的最大值max=1*a+2*b+5*c,计算1,2,3...max,max+1的系数是否为0，若0则不能表示。
代码：
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <cmath>
using namespace std;
int c1[10050], c2[10050];
int main()
{
int a, b, c;
while (~scanf("%d%d%d", &a, &b, &c))
{
if (a == 0 && b == 0 && c == 0)
break;
memset(c1, 0, sizeof(c1));
memset(c2, 0, sizeof(c2));
for (int i = 0; i <= a; i++)
c1[i] = 1;
for (int i = 0; i <= a; i++)
for (int j = 0; j <= b; j++)
c2[i + 2 * j] += c1[i];
for (int i = 0; i <= (a + 2 * b); i++)
{
c1[i] = c2[i];
c2[i] = 0;
}
for (int i = 0; i <= (a + 2 * b); i++)
for (int j = 0; j <= c; j++)
c2[i + 5 * j] += c1[i];
for (int i = 0; i <= (a + 2 * b + 5 * c); i++)
c1[i] = c2[i];
for (int i = 0; i <= (a + 2 * b + 5 * c+1); i++)
if (c1[i] == 0)
{
printf("%d
",i);
break;
}
}
return 0;
}