BZOJ 1041 圆上的整点 数学

 1 #include<bits/stdc++.h>
 2 #define IOS ios::sync_with_stdio(false);//不可再使用scanf printf
 3 #define Max(a, b) ((a) > (b) ? (a) : (b))//禁用于函数，会超时
 4 #define Min(a, b) ((a) < (b) ? (a) : (b))
 5 #define Mem(a) memset(a, 0, sizeof(a))
 6 #define Dis(x, y, x1, y1) ((x - x1) * (x - x1) + (y - y1) * (y - y1))
 7 #define MID(l, r) ((l) + ((r) - (l)) / 2)
 8 #define lson ((o)<<1)
 9 #define rson ((o)<<1|1)
10 #define Accepted 0
11 #pragma comment(linker, "/STACK:102400000,102400000")//栈外挂
12 using namespace std;
13 inline int read()
14 {
15     int x=0,f=1;char ch=getchar();
16     while (ch<‘0‘||ch>‘9‘){if (ch==‘-‘) f=-1;ch=getchar();}
17     while (ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
18     return x*f;
19 }
20 
21 typedef long long ll;
22 const int maxn = 100 + 10;
23 const int MOD = 1000000007;//const引用更快，宏定义也更快
24 const int INF = 1e9 + 7;
25 const double eps = 1e-6;
26 
27 int main()
28 {
29     ll n;
30     cin >> n;
31     while(n % 2 == 0)n /= 2;
32     ll ans = 1;
33     for(ll i = 3; i <= n; i += 2)
34     {
35         if(i % 4 == 3)
36         {
37             while(n % i == 0)n /= i;
38             continue;
39         }
40         if(n % i == 0)
41         {
42             ll tmp = 0;
43             while(n % i == 0)tmp++, n /= i;
44             ans *= (tmp * 2 + 1);
45         }
46     }
47     if(n % 4 == 1 && n > 1)ans *= 3;
48     ans *= 4;
49     cout<<ans<<endl;
50     return Accepted;
51 }