C - Edge （HDU 1033）

For products that are wrapped in small packings it is necessary that the sheet of paper containing the directions for use is folded until its size becomes small enough. We assume that a sheet of paper is rectangular and only folded along lines parallel to its initially shorter edge. The act of folding along such a line, however, can be performed in two directions: either the surface on the top of the sheet is brought together, or the surface on its bottom. In both cases the two parts of the rectangle that are separated by the folding line are laid together neatly and we ignore any differences in thickness of the resulting folded sheet. After several such folding steps have been performed we may unfold the sheet again and take a look at its longer edge holding the sheet so that it appears as a one-dimensional curve, actually a concatenation of line segments. If we move along this curve in a fixed direction we can classify every place where the sheet was folded as either type A meaning a clockwise turn or type V meaning a counter-clockwise turn. Given such a sequence of classifications, produce a drawing of the longer edge of the sheet assuming 90 degree turns at equidistant places.

Input

The input contains several test cases, each on a separate line. Each line contains a nonempty string of characters A and V describing the longer edge of the sheet. You may assume that the length of the string is less than 200. The input file terminates immediately after the last test case.

Output

For each test case generate a PostScript drawing of the edge with commands placed on separate lines. Start every drawing at the coordinates (300, 420) with the command “300 420 moveto”. The first turn occurs at (310, 420) using the command “310 420 lineto”. Continue with clockwise or counter-clockwise turns according to the input string, using a sequence of “x y lineto” commands with the appropriate coordinates. The turning points are separated at a distance of 10 units. Do not forget the end point of the edge and finish each test case by the commands stroke and showpage. You may display such drawings with the gv PostScript interpreter, optionally after a conversion using the ps2ps utility.

输入样例的示意图

Sample Input

V AVV

Sample Output

300 420 moveto 310 420 lineto 310 430 lineto stroke showpage 300 420 moveto 310 420 lineto 310 410 lineto 320 410 lineto 320 420 lineto stroke showpage

题解

题意&思路：

可以想象为一条曲折的马路。起点在（300，400）的位置，马路延伸到（300，420）的位置，然后向右延伸到（310，420）的位置。之后根据输入的A或V，以及前一次延伸的方向（上、下、左、右），来确定延伸的方向，每次延伸10个单位长度。记当前位置为（x，y），记前一次延伸对应的向量（det_x，det_y）为：上（0，10）、下（0，-10）、左（-10，0）、右（10，0）。每次以（det_x，det_y）为参考，确定顺时针或逆时针的延伸方向，并更新（x，y）和（det_x，det_y）。300 420 moveto 310 420 lineto 为固定输出 之后每延伸一次就输出一次x y lineto 末尾再输出 stroke showpage （det_x，det_y）V(逆时针)A(顺时针)上（0，10）左右下（0，-10）右左左（-10，0）下上右（10，0）上下

Code

#include<iostream> #include<string> #include<cstring> using namespace std; int main() { char ch[205]; int x, y, det_x, det_y, len; while(cin >> ch) { len = strlen(ch);//包含VA的字符串的长度 x = 310;//因为前两步时固定的，所以起始位置就设为（310，420） y = 420; det_x = 10; det_y = 0; cout << "300 420 moveto" << endl; cout << "310 420 lineto" << endl; for(int i = 0;i < len; i++) { if(ch[i] == 'V') { if(det_x == 0) { if(det_y == 10) { x -= 10; det_x = -10; det_y = 0; } else { x += 10; det_x = 10; det_y = 0; } } else { if(det_x == 10) { y += 10; det_y = 10; det_x = 0; } else { y -= 10; det_y = -10; det_x = 0; } } } else if(ch[i] == 'A') { if(det_x == 0) { if(det_y == -10) { x -= 10; det_x = -10; det_y = 0; } else { x += 10; det_x = 10; det_y = 0; } } else { if(det_x == -10) { y += 10; det_y = 10; det_x = 0; } else { y -= 10; det_y = -10; det_x = 0; } } } cout << x <<' '<< y <<' '<< "lineto" << endl; } cout << "stroke" << endl; cout << "showpage" << endl; } }