Source code for submission s1110

ants.cpp

  1. /*
  2.  * File:   ants.c
  3.  * Author: cteam057
  4.  *
  5.  * Created on October 27, 2012, 12:39 PM
  6.  */
  7.  
  8. #include <cstdlib>
  9. #include <cstdio>
  10.  
  11. /*
  12.  *
  13.  */
  14.  
  15.  
  16. int cycles, l;
  17.  
  18. class Ant {
  19. public:
  20.     double state, pos;
  21.     int start, moved;
  22.     Ant() {
  23.         state = pos = start = moved = 0;
  24.     }
  25.     void operator=(Ant &b) {
  26.         start=b.start;
  27.         pos=b.pos;
  28.         moved=b.moved;
  29.         state=b.state;
  30.     }
  31. };
  32.  
  33. int comp(const void* a, const void* b) {
  34.     Ant* bx = (Ant *)b;
  35.     Ant* ax = (Ant *)a;
  36.     if(ax->start<bx->start) return -1;
  37.     if(ax->start==bx->start) return 0;
  38.     return 1;
  39. }
  40.  
  41.  
  42. int main(int argc, char** argv) {
  43.     int a;
  44.     int i, p, j;
  45.     char d;
  46.     Ant *ants;
  47.  
  48.     while(scanf("%d %d", &l, &a)==2) {
  49.         ants = new Ant[a];
  50.         cycles=0;
  51.         for(i = 0; i < a; i++) {
  52.             scanf("%d %c", &p, &d);
  53.             ants[i].start=p;
  54.             ants[i].pos=p;
  55.             if(d == 'L') {
  56.                 ants[i].state = -0.5;
  57.                 if(p>cycles) cycles = p;
  58.             } else {
  59.                 ants[i].state = 0.5;
  60.                 if((l-p)>cycles) cycles = l-p;
  61.             };
  62.         }
  63.  
  64.         qsort(ants, a, sizeof(Ant), comp );
  65.  
  66.  
  67.         for(i = 0; i < cycles*2; i++) {
  68.             ants[0].pos += ants[0].state;
  69.             if(ants[0].state) ants[0].moved = 1; else ants[0].moved = 0;
  70.             if(ants[0].pos<=0 || ants[0].pos>=l) ants[0].state=0;
  71.             for(j = 1; j < a; j++) {
  72.                 ants[j].pos += ants[j].state;
  73.                 if(ants[j].state) ants[j].moved = 1; else ants[j].moved = 0;
  74.                 if(ants[j].pos==ants[j-1].pos) {
  75.                     ants[j].state*=-1;
  76.                     ants[j-1].state*=-1;
  77.                 }
  78.                 if(ants[j].pos<=0 || ants[j].pos>=l) ants[j].state=0;
  79.             }
  80.         }
  81.  
  82.         if(cycles==0) {
  83.             if(ants[0].state<0) ants[0].moved=1;
  84.             for(i = 1; i<a-1; i++) {
  85.                 ants[i].moved=0;
  86.             }
  87.             if(ants[a-1].state>0) ants[a-1].moved=1;
  88.         }
  89.  
  90.         printf("The last ant will fall down in %d seconds - started at ", cycles);
  91.         j = 0;
  92.         for(i = 0; i < a; i++) {
  93.             if(ants[i].moved&&j==0) {
  94.                 j++;
  95.                 printf("%d", ants[i].start);
  96.                 continue;
  97.             }
  98.             if(ants[i].moved&&j==1) {
  99.                 printf(" and %d", ants[i].start);
  100.                 break;
  101.             }
  102.         }
  103.         printf(".\n");
  104.  
  105.         delete ants;
  106.     }
  107.     return 0;
  108. }
  109.  
  110.