BestCoder22 1003.NPY and shot 解题报告

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=5144

题目意思：有个人抛物体，已知抛的速度和高度，问可以抛到的最远距离是多少。即水平距离。

　　做的时候是抄公式的，居然过了，幸运幸运............

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cmath>
 4 #include <cstring>
 5 #include <algorithm>
 6 using namespace std;
 7 
 8 const double g = 9.8;
 9 
10 int main()
11 {
12     int T;
13     double h, v;
14     while (scanf("%d", &T) != EOF)
15     {
16         while (T--)
17         {
18             scanf("%lf%lf", &h, &v);
19             double tmp = sqrt(v*v + 1ll * 2 * g * h);
20             double t = tmp / g;
21             double ans = t * v;
22             printf("%.2lf\n", ans);
23         }
24     }
25     return 0;
26 }

View Code

　　乌冬子做的比较正规，是用三分做的，还有浮点精度控制，值得学习 ^_^ （未经他允许就盗他版权，应该不会怪我的......）

 1 #include <algorithm>
 2 #include <cstdio>
 3 #include <cstdlib>
 4 #include <cmath>
 5 #include <iostream>
 6 #include <map>
 7 #include <numeric>
 8 #include <vector>
 9 
10 using namespace std;
11 
12 const double EPS = 1e-8;
13 const double PI = acos(-1.0);
14 const double G = 9.8;
15 
16 int h, v;
17 
18 double F(double ang)
19 {
20   double hv = cos(ang)*v;
21   double vv = sin(ang)*v;
22   double t1 = vv/G;
23   double t2 = sqrt(2*(vv*t1-G*t1*t1/2.0+h)/G);
24   return hv*(t1+t2);
25 }
26 
27 int main()
28 {
29   int kase;
30   scanf("%d", &kase);
31   while (kase--) {
32     scanf("%d%d", &h, &v);
33     double l = 0.0, r = PI/2;
34     while (l < r-EPS) {
35       double d = (r-l)/3.0;
36       double ll = l+d;
37       double rr = r-d;
38       if (F(ll) < F(rr))
39         l = ll;
40       else
41         r = rr;
42     }
43     printf("%.2f\n", F(l));
44   }
45   return 0;
46 }