Sdut 3189 Reverse Rot (water problem)

Reverse Rot Time limit:1000ms Memory limit:65536k Title Description

A very simplistic scheme, which was used at one time to encode information, are to rotate the characters within an alphabet and rewrite them. ROT13 is the variant in which the characters A-Z is rotated places, and it's A commonly used insecure scheme that's at Tempted to "hide" data in many applications from the late 1990\ ' s and into the early 2000\ ' s.

It has been decided by Insecure Inc. to develop a product, "improves" upon this scheme by first reversing the entire s Tring and then rotating it.  As an example, if we apply this scheme to string ABCD with a reversal and rotation of 1, after the reversal we would has And then after rotating this by DCBA 1 position we have the result EDCB .

Your task is to implement this encoding scheme for strings that contain only capital letters, underscores, and periods. Rotations is to be performed using the alphabet order:

    ABCDEFGHIJKLMNOPQRSTUVWXYZ_.

Note that underscore follows Z, and the period follows the underscore. Thus a forward rotation of 1 means \ ' a\ ' is shifted to \ ' B\ ', which is, \ ' a\ ' →\ ' b\ ' ,  \ ' b\ ' →\ ' c\ ' ,  ... ,  \ ' z\ ' →\ ' _\ ' , \ ' _\ ' →\ '. \ ' , and \ '. \ ' →\ ' a\ ' . Likewise a rotation of 3 means \ ' a\ ' →\ ' d\ ' ,  \ ' b\ ' →\ ' e\ ' ,  ... ,  \ '. \ ' →\ ' c\ ' .InputEach input line would consist of an integer N, followed by a string. N is the amount of forward rotation, such. 1≤n≤27 . The string is the message to be encrypted, and would consist of 1 to characters, with the using only capital letters, underscores , and periods. The end of the input would be denoted to a final line with only the number 0.Outputfor each test case, the display the "encrypted" message, the results after being reversed and then shifted.Sample input

1 ABCD3 yo_there.1. DOT14 ROAD9 shifting_and_rotating_is_not_encrypting2 string_to_be_converted1 SNQZDRQDUDQ0

Sample output

Edcbchuhkwbr. Upearoadpwrayf_lwnhaxwh. Rhpwrajax_hmwjhpwraorq. Fgvtgxpqeagdaqvaipktvureverse_rot

Hint Source ACM mid-central reginal programming Contest (MCPC2014) sample program

#include <iostream> #include <algorithm> #include <stdio.h> #include <string.h> #include < stdlib.h> #include <queue> #include <stack> #include <vector> #include <math.h> #include <        Map> #define INF 0x3f3f3f3fusing namespace Std;char a[101];int n;int main () {while (scanf ("%d", &n)!=eof) {        if (n = = 0) {break;        } scanf ("%s", a);        int len = strlen (a);        n = n%28;            for (int i=len-1;i>=0;i--) {if (a[i] = = '. ')                {if (n = =) {printf ("_");                } else {printf ("%c", ' A ' +n-1);            } continue;                } if (a[i] = = ' _ ') {if (n = = 1) {printf (".");                } else {printf ("%c", ' A ' +n-2);      }          Continue } if (a[i]+n> ' z ') {if (a[i]+n-' z ' = = 1) {printf (                "_");                } else if (a[i]+n-' Z ' = = 2) {printf (".");                } else {printf ("%c", ' A ' +a[i]+n-' Z '-3);            }} else {printf ("%c", a[i]+n);    }} printf ("\ n"); } return 0;}

Sdut 3189 Reverse Rot (water problem)