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  1. #include <iostream>
  2. #include <stdio.h>
  3. #include <stdlib.h>
  4.  
  5. using namespace std;
  6.  
  7. int* buildSnailReverse( int* a, int w, int h )
  8. {
  9.     int
  10.     u[] = { 1, w,-1,-w},
  11.     d = w < h,
  12.     z = ((d? w: h) - 1 >> 1) * (w + 1) + (~w & d),
  13.     n = d? h - w: w - h,
  14.     p = 0,
  15.     c = n,
  16.     i = 0;
  17.     while(i < w * h)
  18.     {
  19.         a[z] = ++i;
  20.         z += u[d];
  21.         if (!c--)
  22.         {
  23.             ++d &= 3, c = n ^= p ^= n ^= p;
  24.             p++;
  25.         }
  26.     }
  27.     return a;
  28. }
  29.  
  30. void printArray(int* a, int w, int h)
  31. {
  32. 	for(int y = 0; y < h; y++)
  33. 	{
  34. 		for(int x = 0; x < w; x++)
  35. 		    printf("%3d", a[x + y * w]);
  36. 	    cout << endl;
  37. 	}
  38. }
  39.  
  40. int main()
  41. {
  42.     int w, h;
  43.     cin >> w >> h;
  44.     int* a = new int[w * h];
  45.     buildSnailReverse(a, w, h);
  46.     printArray(a, w, h);
  47.     delete[] a;
  48.     fflush(stdin);
  49.     getchar();
  50.     return 0;
  51. }
Success #stdin #stdout 0s 15240KB
comments (?)
stdin 
8
5
stdout 
 33 34 35 36 37 38 39 40
 32 13 14 15 16 17 18 19
 31 12  1  2  3  4  5 20
 30 11 10  9  8  7  6 21
 29 28 27 26 25 24 23 22
https://ideone.com/QZmQDg
snail
language:
C++ (gcc 8.3)
created:
7 years ago
visibility:
secret

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