POJ 3414 Pots bfs打印方案
题目： http://poj.org/problem?id=3414
很好玩的一个题。关键是又16ms 1A了，没有debug的日子才是好日子。。
1 #include <stdio.h> 2 #include <string.h> 3 #include <queue> 4 #include <algorithm> 5 #include <stack> 6 using namespace std; 7 int a, b, c; 8 bool vis[110][110]; 9 enum Ways{FILL_A, FILL_B, DROP_A, DROP_B, POUR_AB, POUR_BA}; 10 11 struct Path 12 { 13 int px, py; 14 Ways way; 15 }path[110][110]; 16 17 struct status 18 { 19 int x, y, step; 20 }; 21 22 void print_path(int x, int y) 23 { 24 stack<struct Path>s; 25 while(!(x == 0 && y == 0)) 26 { 27 s.push(path[x][y]); 28 int tx = path[x][y].px; 29 int ty = path[x][y].py; 30 x = tx; 31 y = ty; 32 } 33 while(!s.empty()) 34 { 35 switch(s.top().way) 36 { 37 case FILL_A: printf("FILL(1)\n");break; 38 case FILL_B: printf("FILL(2)\n");break; 39 case DROP_A: printf("DROP(1)\n");break; 40 case DROP_B: printf("DROP(2)\n");break; 41 case POUR_AB: printf("POUR(1,2)\n");break; 42 case POUR_BA: printf("POUR(2,1)\n");break; 43 } 44 s.pop(); 45 } 46 } 47 48 queue<struct status>q; 49 void bfs() 50 { 51 while(!q.empty()) 52 { 53 struct status u = q.front(); 54 q.pop(); 55 if(u.x == c || u.y == c) 56 { 57 printf("%d\n", u.step); 58 print_path(u.x, u.y); 59 return; 60 } 61 62 if(u.x < a && !vis[a][u.y]) 63 { 64 q.push((struct status){a, u.y, u.step+1}); 65 vis[a][u.y] = 1; 66 path[a][u.y] = (struct Path){u.x, u.y, FILL_A}; 67 } 68 69 if(u.y < b && !vis[u.x][b]) 70 { 71 q.push((struct status){u.x, b, u.step+1}); 72 vis[u.x][b] = 1; 73 path[u.x][b] = (struct Path){u.x, u.y, FILL_B}; 74 } 75 76 if(u.x > 0 && !vis[0][u.y]) 77 { 78 q.push((struct status){0, u.y, u.step+1}); 79 vis[0][u.y] = 1; 80 path[0][u.y] = (struct Path){u.x, u.y, DROP_A}; 81 } 82 83 if(u.y > 0 && !vis[u.x][0]) 84 { 85 q.push((struct status){u.x, 0, u.step+1}); 86 vis[u.x][0] = 1; 87 path[u.x][0] = (struct Path){u.x, u.y, DROP_B}; 88 } 89 90 if(u.x > 0 && u.y < b) 91 { 92 int tmp = min(u.x, b-u.y); 93 if(!vis[u.x-tmp][u.y+tmp]) 94 { 95 q.push((struct status){u.x-tmp, u.y+tmp, u.step+1}); 96 vis[u.x-tmp][u.y+tmp] = 1; 97 path[u.x-tmp][u.y+tmp] = (struct Path){u.x, u.y, POUR_AB}; 98 } 99 } 100 101 if(u.x < a && u.y > 0) 102 { 103 int tmp = min(a-u.x, u.y); 104 if(!vis[u.x+tmp][u.y-tmp]) 105 { 106 q.push((struct status){u.x+tmp, u.y-tmp, u.step+1}); 107 vis[u.x+tmp][u.y-tmp] = 1; 108 path[u.x+tmp][u.y-tmp] = (struct Path){u.x, u.y, POUR_BA}; 109 } 110 } 111 } 112 printf("impossible\n"); 113 } 114 115 int main() 116 { 117 scanf("%d %d %d", &a, &b, &c); 118 memset(vis, 0, sizeof(vis)); 119 q.push((struct status){0, 0, 0}); 120 vis[0][0] = 1; 121 bfs(); 122 return 0; 123 }
