->题目请戳这里<-
题目大意:在一个h*w的场地内玩冰壶游戏,0代表空地,1代表障碍,2代表冰壶起始位置,3代表目标位置。现在要把冰壶挪到目标位置,冰壶只能往上下左右4个方向走,冰壶隔壁如果是障碍物,就不能往该方向走。冰壶走了就不会停下来,除非碰到障碍物,碰到障碍物后冰壶停止,障碍物消失(先停止再消失),冰壶当然不能出界。求冰壶能否在10步内(包括10步)到达目的地,如果能,输出最小步数,不能输出-1。
题目分析:题目要求最小步数,考虑到场地最大20*20,并且步数限制不超过10步,考虑用dfs回溯遍历所有解,取最小的。注意输入的时候是先输入列,再输入行,很条件反射的先处理行再处理列,提交上去果断WA,还sb的调了半天,测了n组数据才发现>o<。。。。中招的童鞋请自行了断。。。
详情请见代码:
#include <iostream> #include<cstdio> #include<cstring> using namespace std; const int N = 30; int map[N][N]; int h,w; int si,sj,ei,ej; struct node { int x,y; }path[20]; int ans; int dir[][2] = {{1,0},{-1,0},{0,1},{0,-1}}; int isok(int x,int y) { return (x > 0 && y > 0 && x <= h && y <= w); } void dfs(int curi,int curj,int step) { path[step].x = curi; path[step].y = curj; if(step > 10) return; if(curi == ei && curj == ej) { if(step < ans) ans = step; //printf("path:%d\n",step); //for(int i = 0;i <= step;i ++) // printf("%d %d\n",path[i].x,path[i].y); return; } int ti,tj,i; for(i = 0;i < 4;i ++) { ti = curi; tj = curj; if(map[ti + dir[i][0]][tj + dir[i][1]] != 1)//要走的方向上相邻的不是障碍,说明能走 { while(isok(ti,tj) && map[ti][tj] == 0) { ti += dir[i][0]; tj += dir[i][1]; } if(map[ti][tj] == 1)// { map[ti][tj] = 0; dfs(ti - dir[i][0],tj - dir[i][1],step + 1); map[ti][tj] = 1; } if(map[ti][tj] == 3) dfs(ti,tj,step + 1); } } } int main() { int i,j; while(scanf("%d%d",&w,&h),(h + w)) { memset(map,0,sizeof(map)); for(i = 1;i <= h;i ++) { for(j = 1;j <= w;j ++) { scanf("%d",&map[i][j]); if(map[i][j] == 2) { si = i; sj = j; } else { if(map[i][j] == 3) { ei = i; ej = j; } } } } ans = 10000; map[si][sj] = 0; //printf("si:%d sj:%d\n",si,sj); dfs(si,sj,0); //printf("ans:"); if(ans > 10) printf("-1\n"); else printf("%d\n",ans); } return 0; } /* 2 1 3 2 6 6 1 0 0 2 1 0 1 1 0 0 0 0 0 0 0 0 0 3 0 0 0 0 0 0 1 0 0 0 0 1 0 1 1 1 1 1 6 1 1 1 2 1 1 3 6 1 1 0 2 1 1 3 12 1 2 0 1 1 1 1 1 1 1 1 1 3 13 1 2 0 1 1 1 1 1 1 1 1 1 1 3 0 0 */ /* 18 14 1 0 1 0 1 1 1 0 0 0 0 1 1 1 0 1 0 3 0 1 0 1 0 1 1 0 0 0 0 1 1 0 1 1 1 0 0 0 0 0 0 1 0 0 1 1 0 0 0 0 1 0 1 0 1 1 0 1 1 1 1 1 1 0 1 1 1 1 0 1 1 0 1 1 1 0 0 1 1 0 0 2 1 1 1 1 1 1 0 1 0 1 1 0 0 0 0 0 1 1 1 1 0 0 0 1 1 0 1 0 0 1 1 1 0 1 0 1 0 0 0 0 1 0 1 0 0 1 1 1 0 1 1 1 0 0 1 0 1 0 0 0 0 0 0 1 1 1 0 1 0 1 1 1 0 1 1 1 1 1 0 0 1 0 0 1 1 1 0 0 1 0 1 0 1 1 1 0 0 0 0 1 0 0 1 0 1 0 1 0 1 1 1 1 0 1 0 1 1 1 1 1 0 1 1 1 0 1 0 0 0 0 1 1 1 0 1 0 0 0 1 1 1 0 1 1 1 1 1 0 1 0 0 0 0 0 1 1 0 1 0 0 0 0 1 1 1 1 0 0 1 0 14 12 0 1 0 0 1 1 0 1 0 1 0 1 2 1 0 0 0 0 0 0 0 0 0 1 0 0 1 1 1 0 0 1 1 1 1 0 0 0 0 0 1 0 1 0 1 1 1 0 1 0 3 1 1 0 0 0 0 1 0 0 1 0 1 0 1 0 0 0 1 0 0 0 0 1 0 1 1 1 0 1 1 0 0 0 1 0 1 0 0 1 0 0 0 1 0 0 0 0 1 0 0 1 1 1 1 1 1 0 0 0 0 0 0 1 0 1 0 1 0 1 1 0 0 0 0 0 1 1 1 1 1 0 0 1 0 0 0 1 1 1 0 0 1 1 1 0 1 1 1 1 1 0 0 0 0 0 0 1 0 0 1 1 1 0 1 0 1 0 9 13 1 0 1 1 0 0 1 0 0 0 0 1 1 1 1 1 0 1 1 1 0 1 0 0 0 0 1 1 1 1 0 0 0 0 1 0 1 1 0 1 1 1 1 1 1 0 1 0 1 0 1 1 0 0 0 1 0 3 1 1 0 0 1 0 1 0 1 1 0 0 0 1 2 1 1 0 0 1 0 0 1 0 1 0 1 0 0 1 1 0 1 0 1 1 1 0 0 1 1 0 0 1 0 0 1 0 0 0 1 1 1 0 0 1 1 1 0 2 7 3 0 1 1 0 0 1 0 1 0 0 1 2 0 4 13 1 0 1 0 1 0 0 1 1 0 1 1 3 1 0 0 1 0 1 1 0 1 1 0 0 0 0 0 2 1 0 1 1 1 0 0 1 1 1 1 1 0 0 0 0 0 1 0 1 0 0 1 14 19 0 1 0 1 1 0 0 1 1 1 1 1 0 0 1 0 0 0 3 0 0 1 1 1 2 0 1 1 0 1 1 1 0 1 0 0 0 0 1 0 0 0 0 1 1 0 0 0 0 1 0 0 1 0 0 0 0 0 1 1 0 1 1 0 1 0 0 1 0 1 1 0 0 1 1 1 1 1 0 1 1 0 1 0 1 0 0 0 1 0 0 0 1 0 1 0 0 0 1 0 1 0 0 1 0 0 1 0 1 0 1 0 0 1 0 0 0 1 0 0 0 0 1 1 0 0 0 1 0 0 1 1 0 1 1 1 0 1 0 1 1 1 0 1 1 0 0 1 0 0 0 0 1 1 1 0 1 1 0 1 1 1 1 1 1 1 1 0 0 1 1 0 0 1 0 1 1 1 1 0 0 1 1 1 0 1 0 1 1 0 1 1 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 1 0 1 0 1 0 0 1 0 1 0 0 1 1 0 1 0 1 0 1 0 0 0 1 1 0 0 1 1 1 1 0 1 1 0 1 1 0 0 0 1 0 1 0 1 1 1 0 0 1 0 1 1 0 0 0 1 0 0 5 4 1 0 0 1 0 3 1 1 1 2 1 0 0 1 1 1 1 0 0 0 18 6 0 1 1 0 0 1 0 0 0 0 0 1 0 1 1 1 0 0 1 0 1 0 1 1 0 0 1 1 1 0 0 0 1 1 1 1 0 1 0 0 0 1 0 0 0 1 0 1 0 1 0 1 1 1 1 1 0 0 0 1 0 0 0 1 1 0 1 0 1 2 0 0 1 0 3 1 1 1 0 0 0 0 1 1 0 0 0 0 1 1 1 1 0 1 1 0 1 0 1 1 0 1 0 0 1 1 1 0 19 17 1 1 1 1 0 1 0 0 1 0 0 0 0 0 1 1 0 0 0 0 0 1 1 0 0 0 0 0 1 0 0 0 1 0 0 0 0 1 0 1 0 1 1 1 0 0 1 0 1 0 1 1 1 1 1 1 0 1 0 1 1 0 0 1 0 0 1 0 1 0 1 1 0 0 0 0 1 0 1 0 0 1 1 1 1 0 0 0 1 0 1 0 0 0 0 1 0 0 0 1 1 1 0 1 1 1 1 1 0 1 1 1 0 0 1 0 0 0 0 1 1 3 1 1 0 0 0 0 1 0 0 0 0 0 0 1 1 0 1 0 0 0 0 1 1 0 0 1 0 1 1 0 0 1 1 0 0 0 1 0 1 1 1 1 0 1 0 0 0 2 1 1 1 1 0 1 1 0 1 0 0 1 0 0 0 0 0 1 1 0 0 0 0 1 0 0 0 1 1 0 1 0 1 1 1 0 0 1 0 0 1 0 0 0 0 0 0 1 1 1 0 0 1 1 0 1 0 1 1 1 0 0 0 1 0 0 0 1 1 0 0 0 1 0 0 1 1 0 0 1 1 0 0 0 0 1 1 0 0 0 1 0 0 1 1 0 1 0 0 0 1 1 0 1 1 1 0 0 1 1 1 1 0 1 0 0 1 0 1 1 1 0 0 1 0 1 0 1 1 0 1 0 1 1 1 0 1 0 0 0 1 1 1 1 1 1 0 1 1 1 0 0 0 18 2 1 1 0 1 0 1 1 0 1 0 0 3 0 0 1 0 1 0 0 0 0 1 0 1 0 1 1 2 1 1 0 1 0 0 1 0 7 10 1 0 0 0 1 1 0 1 0 1 1 1 0 1 0 1 1 0 1 1 1 0 1 1 1 0 1 1 1 1 0 0 0 1 0 1 1 0 1 2 1 0 0 3 0 0 1 0 0 0 1 1 1 0 0 0 1 0 1 0 1 0 0 1 1 1 1 1 1 0 14 6 0 0 1 0 0 0 0 1 1 0 1 1 1 0 0 0 1 0 1 0 1 1 1 1 1 1 1 1 1 1 0 2 1 1 0 0 1 0 0 0 0 1 1 0 1 1 1 1 1 1 1 1 1 1 1 0 1 0 1 1 1 0 1 1 0 1 1 0 0 0 1 0 1 0 0 1 0 0 1 0 0 0 0 3 4 8 0 1 0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0 0 0 3 0 1 0 1 0 1 0 1 0 0 2 */ //136K 297MS