【HDOJ】1903 Exchange Rates

水DP。精度很坑。

 /* hdoj 1903 */
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
 #include <cmath>

 #define MAXN 505

 double a[MAXN];
 double dp[MAXN][];

 double max(double a, double b) {
     return a>b ? a:b;
 }

 inline double cal(double x, double f) {
     return floor(x*f*0.97*.)/100.0;
 }

 int main() {
     int t, n;
     int i, j, k;
     double tmp;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
     #endif

     while (scanf("%d", &n)!=EOF && n) {
         for (i=; i<=n; ++i)
             scanf("%lf", &a[i]);
         dp[][] = 0.0;
         dp[][] = 1000.0;
         for (i=; i<=n; ++i) {
             dp[i][] = max(dp[i-][], cal(dp[i-][], ./a[i]));
             dp[i][] = max(dp[i-][], cal(dp[i-][],    a[i]));
         }
         printf("%.2lf\n", dp[n][]);
     }

     return ;
 }