Source code for submission s1013

ants.cpp

  1. #include <iostream>
  2. #include <cstdlib>
  3. #include <cstdio>
  4.  
  5. using namespace std;
  6.  
  7. struct anti{
  8. 	char Dir;
  9. 	int Pos;
  10. 	int StartPos;
  11. };
  12.  
  13. void changeDir( char & dir){
  14. 	if (dir == 'R') dir = 'L';
  15. 	else if (dir == 'L') dir = 'R';
  16. }
  17.  
  18.  
  19. int main (){
  20.  
  21. 	int i,Size, Time=0, Num, LP=0, stepped;
  22.  
  23. 	bool felt=false;
  24.  
  25. 	cin >> Size >> Num;
  26. 	anti * Ants = new anti [Size];
  27.  
  28. 	for (i=0;i<Num;i++){
  29. 		cin >> Ants[i].Pos >> Ants[i].Dir;		
  30. 		Ants[i].StartPos = Ants[i].Pos;
  31. 	}
  32.  
  33. 	for (i=0;i<Num;i++){
  34. 		for (int j = 0;j<Num-1-i;j++){
  35. 			if (Ants[j].Pos>Ants[j+1].Pos){
  36. 				swap (Ants[j].Pos,Ants[j+1].Pos);
  37. 				swap (Ants[j].Dir,Ants[j+1].Dir);
  38. 				swap (Ants[j].StartPos,Ants[j+1].StartPos);
  39. 			}
  40. 		}
  41. 	}
  42.  
  43. 	stepped = -1;
  44. 	while (1){
  45. 		if (LP == Num-1){ 
  46. 			if (Ants[LP].Dir=='L') Time +=Ants[LP].Pos;
  47. 				else Time+= (Size -Ants[LP].Pos);
  48. 			cout << "The last ant will fall down in "<< Time << " seconds - started at " << 				Ants[LP].StartPos<<"."<<endl;
  49. 			return 0; 
  50. 		}
  51.  
  52. 		if (Ants[LP].Pos==0 && Ants[LP].Dir=='L') { LP++; felt=true;}
  53. 		if (Ants[Num-1].Pos==Size && Ants[Num-1].Dir=='R') {
  54. 			if (felt == true && Num == (LP+1) ){
  55. 				cout << "The last ant will fall down in "<< Time << " seconds - started at " 					<<	Ants[LP-1].StartPos<<" and "<<Ants[Num-1].StartPos<< 					"."<<endl;
  56. 				return 0; 
  57. 			}
  58. 			Num--;
  59. 		}
  60. 		felt = false;
  61.  
  62.  
  63. 		for (i=LP; i<Num; i++){
  64. 			if ((i+1) < Num && Ants[i].Pos == Ants[i+1].Pos){
  65. 				Ants[i].Dir = 'L';
  66. 				Ants[i+1].Dir = 'R';
  67. 				Ants[i].Pos--;
  68. 				Ants[i+1].Pos++;				
  69. 				stepped = i+1;
  70. 				continue;
  71. 			}
  72. 			else if ((i+1) < Num && Ants[i].Pos == (Ants[i+1].Pos-1) && Ants[i].Dir == 'R' 
  73. 												&& Ants[i+1].Dir == 'L'){
  74. 				Ants[i].Dir = 'L';
  75. 				Ants[i+1].Dir = 'R';
  76. 				stepped = i+1;
  77. 				continue;	
  78. 			}
  79. 			else if(i != stepped){
  80. 				if (Ants[i].Dir == 'R') Ants[i].Pos++;
  81. 				if (Ants[i].Dir == 'L') Ants[i].Pos--;
  82. 				stepped = -1;
  83. 			}
  84. 		}
  85. //-----------------------------------------------------------------------------
  86.  
  87. 		Time++;
  88. 	}
  89.  
  90.  
  91. return 0;
  92. }
  93.