C Looooops(扩展欧几里得)
2015-08-23 13:22
429 查看
C Looooops
Time Limit: 1000MS Memory Limit: 65536K
Total Submissions: 20128 Accepted: 5405
Description
A Compiler Mystery: We are given a C-language style for loop of type
for (variable = A; variable != B; variable += C)
statement;
I.e., a loop which starts by setting variable to value A and while variable is not equal to B, repeats statement followed by increasing the variable by C. We want to know how many times does the statement get executed for particular values of A, B and C, assuming that all arithmetics is calculated in a k-bit unsigned integer type (with values 0 <= x < 2k) modulo 2k.
Input
The input consists of several instances. Each instance is described by a single line with four integers A, B, C, k separated by a single space. The integer k (1 <= k <= 32) is the number of bits of the control variable of the loop and A, B, C (0 <= A, B, C < 2k) are the parameters of the loop.
The input is finished by a line containing four zeros.
Output
The output consists of several lines corresponding to the instances on the input. The i-th line contains either the number of executions of the statement in the i-th instance (a single integer number) or the word FOREVER if the loop does not terminate.
Sample Input
3 3 2 16
3 7 2 16
7 3 2 16
3 4 2 16
0 0 0 0
Sample Output
0
2
32766
FOREVER
Source
CTU Open 2004
看了题解还是不太懂,有时间去请教一下大神
Time Limit: 1000MS Memory Limit: 65536K
Total Submissions: 20128 Accepted: 5405
Description
A Compiler Mystery: We are given a C-language style for loop of type
for (variable = A; variable != B; variable += C)
statement;
I.e., a loop which starts by setting variable to value A and while variable is not equal to B, repeats statement followed by increasing the variable by C. We want to know how many times does the statement get executed for particular values of A, B and C, assuming that all arithmetics is calculated in a k-bit unsigned integer type (with values 0 <= x < 2k) modulo 2k.
Input
The input consists of several instances. Each instance is described by a single line with four integers A, B, C, k separated by a single space. The integer k (1 <= k <= 32) is the number of bits of the control variable of the loop and A, B, C (0 <= A, B, C < 2k) are the parameters of the loop.
The input is finished by a line containing four zeros.
Output
The output consists of several lines corresponding to the instances on the input. The i-th line contains either the number of executions of the statement in the i-th instance (a single integer number) or the word FOREVER if the loop does not terminate.
Sample Input
3 3 2 16
3 7 2 16
7 3 2 16
3 4 2 16
0 0 0 0
Sample Output
0
2
32766
FOREVER
Source
CTU Open 2004
看了题解还是不太懂,有时间去请教一下大神
#include <set> #include <map> #include <list> #include <stack> #include <cmath> #include <queue> #include <string> #include <cstdio> #include <cstdlib> #include <cstring> #include <iostream> #include <algorithm> #define PI cos(-1.0) #define RR freopen("input.txt","r",stdin) using namespace std; typedef long long LL; LL ExtendedEuclid(LL a,LL b,LL &x,LL &y) { if(b==0) { x=1; y=0; return a; } LL d=ExtendedEuclid(b,a%b,x,y); LL xt=x; x=y; y=xt-a/b*y; return d; } int main() { LL A,B,C,K; while(cin>>A>>B>>C>>K) { if(!A&&!B&&!C&&!K) { break; } LL a=C; LL b=B-A; LL n=(LL)1<<K; LL x,y; LL d=ExtendedEuclid(a,n,x,y); if(b%d!=0) { cout<<"FOREVER"<<endl; } else { x=(x*(b/d))%n; x=(x%(n/d)+n/d)%(n/d); cout<<x<<endl; } } return 0; }
相关文章推荐
- C Looooops(扩展欧几里得)
- TOMCAT的框架结构
- tomcat负载均衡
- win7 下jdk+tomcat配置
- mac 下更新 .bash_profile 文件
- Nginx - Windows下Nginx基本安装和配置
- Linux - Gentoo Installation with awesome desktop
- hadoop压缩算法的总结
- Linux下搭建python + nodejs + express环境
- elk分析nginx访问日志
- squid的安装与配置
- Linux的命令帮助获取方式及一些基础命令小结
- centos下nginx启动脚本和chkconfig管
- popen() 函数用法
- CentOS 6.5 64位安装mysql 5.6
- HDU 5406 DP topo序
- linux kernel 0.11 bootsect
- 清空select标签中option选项的3种不同方式
- Shell编程之IF条件语句各种案例演练
- 淘宝应对"双11"的技术架构分析