AtCoder Grand Contest 001

B - Mysterious Light

题意：从一个正三角形边上一点出发，遇到边和已走过的边则反弹，问最终路径长度

思路：GCD

数据爆long long

 1 #pragma comment(linker, "/STACK:102c000000,102c000000")
 2 #include <iostream>
 3 #include <cstdio>
 4 #include <cstring>
 5 #include <sstream>
 6 #include <string>
 7 #include <algorithm>
 8 #include <list>
 9 #include <map>
10 #include <vector>
11 #include <queue>
12 #include <stack>
13 #include <cmath>
14 #include <cstdlib>
15 // #include <conio.h>
16 using namespace std;
17 #define clc(a,b) memset(a,b,sizeof(a))
18 #define inf 0x3f3f3f3f
19 #define lson l,mid,rt<<1
20 #define rson mid+1,r,rt<<1|1
21 const int N = 3*1e6+10;
22 const int MOD = 1e9+7;
23 #define LL long long
24 #define mi() (l+r)>>1
25 double const pi = acos(-1);
26 
27 void fre() {
28     freopen("in.txt","r",stdin);
29 }
30 
31 // inline int r() {
32 //     int x=0,f=1;char ch=getchar();
33 //     while(ch>'9'||ch<'0') {if(ch=='-') f=-1;ch=getchar();}
34 //     while(ch>='0'&&ch<='9') { x=x*10+ch-'0';ch=getchar();}return x*f;
35 // }
36 
37 LL Gcd(LL a,LL b){ return b? Gcd(b, a % b) : a; }
38 int main(){
39     LL n,x; cin >> n >> x;
40     LL d = Gcd(n,x);
41     n/=d;
42     unsigned long long ans=d*3*(n-1);
43     printf("%llu\n",ans);
44 }
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posted @ 2016-07-17 09:17  yyblues  阅读(300)  评论(0)  编辑  收藏  举报