[HDOJ5879]Cure（求极限，打表）

Posted 2020-08-09

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=5879

 1 #include <algorithm>
 2 #include <iostream>
 3 #include <iomanip>
 4 #include <cstring>
 5 #include <climits>
 6 #include <complex>
 7 #include <fstream>
 8 #include <cassert>
 9 #include <cstdio>
10 #include <bitset>
11 #include <vector>
12 #include <deque>
13 #include <queue>
14 #include <stack>
15 #include <ctime>
16 #include <set>
17 #include <map>
18 #include <cmath>
19 using namespace std;
20 #define fr first
21 #define sc second
22 #define cl clear
23 #define BUG puts("here!!!")
24 #define W(a) while(a--)
25 #define pb(a) push_back(a)
26 #define Rint(a) scanf("%d", &a)
27 #define Rll(a) scanf("%I64d", &a)
28 #define Rs(a) scanf("%s", a)
29 #define Cin(a) cin >> a
30 #define FRead() freopen("in", "r", stdin)
31 #define FWrite() freopen("out", "w", stdout)
32 #define Rep(i, len) for(int i = 0; i < (len); i++)
33 #define For(i, a, len) for(int i = (a); i < (len); i++)
34 #define Cls(a) memset((a), 0, sizeof(a))
35 #define Clr(a, x) memset((a), (x), sizeof(a))
36 #define Full(a) memset((a), 0x7f7f7f, sizeof(a))
37 #define lrt rt << 1
38 #define rrt rt << 1 | 1
39 #define pi 3.14159265359
40 #define RT return
41 #define lowbit(x) x & (-x)
42 #define onecnt(x) __builtin_popcount(x)
43 typedef long long LL;
44 typedef long double LD;
45 typedef unsigned long long ULL;
46 typedef pair<int, int> pii;
47 typedef pair<string, int> psi;
48 typedef pair<LL, LL> pll;
49 typedef map<string, int> msi;
50 typedef vector<int> vi;
51 typedef vector<LL> vl;
52 typedef vector<vl> vvl;
53 typedef vector<bool> vb;
54 
55 const int maxn = 1000010;
56 char tn[2*maxn];
57 double ret[maxn];
58 LL n;
59 
60 signed main() {
61     Cls(ret);
62     double tmp = .0;
63     For(i, 1, 1000000) {
64         tmp += double(1.0)/double((LL)i*i);
65         ret[i] = tmp;
66     }
67     while(~Rs(tn)) {
68         int len = strlen(tn);
69         if(len >= 7) n = 999999;
70         else sscanf(tn, "%I64d", &n);
71         printf("%.5lf\n", ret[n]);
72     }
73     RT 0;
74 }