[模版]模版留着以后用(不定期更新)

 1 /*并查集*/
 2 #define MAXN 10000
 3 int pre[MAXN];
 4 int find(int x) {
 5     return x == pre[x] ? x : pre[x] = find(pre[x]);
 6 }
 7 void merge(int x, int y) {
 8     x = find(x);
 9     y = find(y);
10     if (x != y) {
11         pre[x] = y;
12     }
13 }
14 
15 /*快速幂*/
16 #define MOD 10
17 __int64 quickmul(int x, int n) {
18     __int64 ans = 1;
19     __int64 t = n;
20     while (n) {
21         if (n & 1) {
22             ans = (ans * t) % MOD;
23         }
24         t = t * t % MOD;
25         n >>= 1;
26     }
27     return ans;
28 }
29 
30 /*矩阵快速幂*/
31 #define MOD 10
32 #define MAXN 10
33 
34 struct Matrix {
35     int m[MAXN][MAXN];
36     int r, c;
37     Matrix() {
38         r = c = 0;
39         memset(m, 0, sizeof(m));
40     }
41 };
42 
43 Matrix mul(Matrix m1, Matrix m2, int mod) {
44     Matrix ans = Matrix();
45     ans.r = m1.r;
46     ans.c = m2.c;
47     for (int i = 1; i <= m1.r; i++) {
48         for (int j = 1; j <= m2.r; j++) {
49             if (m1.m[i][j]) {    //优化
50                 for (int k = 1; k <= m2.c; k++) {
51                     ans.m[i][k] = (ans.m[i][k] + m1.m[i][j] * m2.m[j][k]) % mod;
52                 }
53             }
54         }
55     }
56     return ans;
57 }
58 
59 Matrix quickmul(Matrix m, int n, int mod) {
60     Matrix ans = Matrix();
61     for (int i = 1; i <= m.r; i++) {
62         ans.m[i][i] = 1;
63     }
64     ans.r = m.r;
65     ans.c = m.c;
66     while (n) {
67         if (n & 1) {
68             ans = mul(m, ans, mod);
69         }
70         m = mul(m, m, mod);
71         n >>= 1;
72     }
73     return ans;
74 }

 1 /*埃氏筛*/
 2 double s_MAXN = sqrt(MAXN);
 3 bool pri[MAXN + 1];
 4 
 5 void prilist()
 6 {
 7     memset(pri, true, sizeof(pri));
 8     pri[1] = false;
 9     for (int i = 2; i <= int(s_MAXN); i++)
10     {
11         if (pri[i] == true)
12         {
13             for (int j = 2; j <= MAXN / i; j++)
14             {
15                 pri[i*j] = false;
16             }
17         }
18     }
19 }