Reverse Rot: Difference between revisions

From programming_contest
Jump to navigation Jump to search
imported>Ww109
imported>Ww109
Line 1: Line 1:
[http://speedyguy17.info/data/mcpc/mcpc2013/mcpc2013/pdfs/C%20Missing%20Pages.pdf Original Description]
[http://speedyguy17.info/data/mcpc/mcpc2013/mcpc2013/pdfs/C%20Missing%20Pages.pdf Original Description]
== Idea ==  
== Idea ==  
Use the symmetry of the structure: the first two pages are bundled with the last two and so on.
Manipulate the ASCII value of chars


Given an odd P, the other three pages are P + 1, N - P and N - P + 1. For an even P, the other three pages are P - 1, N - P + 1 and N - P + 2.
Handle special cases of moving them to the end of normal ones. Then use module to get the result after shift


== Code ==  
== Code ==  

Revision as of 17:42, 5 December 2015

Original Description

Idea

Manipulate the ASCII value of chars

Handle special cases of moving them to the end of normal ones. Then use module to get the result after shift

Code

import java.util.*;
public class Reverse_Rot {

	public static void encrypt(String s, int k){
		for(int i = s.length()-1; i>=0; i--){
			char c = s.charAt(i);
			if(c == 95) c = 91;
			if(c == 46) c = 92;
			c = (char)(c + k);
			c = (char)((c - 'A') % 28 + 'A');
			if(c == 91) c = 95;
			if(c == 92) c = 46;
			System.out.print(c);
		}
		System.out.println();
	}
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Scanner scan = new Scanner(System.in);
		while(scan.hasNext()){
			int k = scan.nextInt();
			if(k == 0)
				break;
			String s = scan.next();
			encrypt(s,k);
		}

	}

}