【模板】有理数取余

嘟嘟嘟

a / b % p = a * b-1 % p,又因为p是质数,根据费马小定理=> a * b-1 % p = a * bp-2 % p。

看数据范围,不想写高精,就改了一下快读。

 1 #include<cstdio>
 2 #include<iostream>
 3 #include<cmath>
 4 #include<algorithm>
 5 #include<cstring>
 6 #include<cstdlib>
 7 #include<cctype>
 8 #include<vector>
 9 #include<stack>
10 #include<queue>
11 using namespace std;
12 #define enter puts("") 
13 #define space putchar(' ')
14 #define Mem(a, x) memset(a, x, sizeof(a))
15 #define rg register
16 typedef long long ll;
17 typedef double db;
18 const int INF = 0x3f3f3f3f;
19 const db eps = 1e-8;
20 const int mod = 19260817;
21 inline ll read()
22 {
23     ll ans = 0;
24     char ch = getchar(), last = ' ';
25     while(!isdigit(ch)) {last = ch; ch = getchar();}
26     while(isdigit(ch)) {ans = ans * 10 % mod + ch - '0'; ch = getchar();}
27     ans %= mod;
28     if(last == '-') ans = -ans;
29     return ans;
30 }
31 inline void write(ll x)
32 {
33     if(x < 0) x = -x, putchar('-');
34     if(x >= 10) write(x / 10);
35     putchar(x % 10 + '0');
36 }
37 
38 ll quickpow(ll a, int b)
39 {
40     ll ret = 1;
41     while(b)
42     {
43         if(b & 1) ret = ret * a % mod;
44         a = a * a % mod; b >>= 1;
45     }
46     return ret;
47 }
48 
49 int main()
50 {
51     ll a = read(), b = read();
52     if(!b) {printf("Angry!
"); return 0;}
53     ll ans = a * quickpow(b, mod - 2) % mod;
54     write(ans); enter;
55 }
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原文地址:https://www.cnblogs.com/mrclr/p/9737126.html