标签：style blog class code ext color
Joe
works in a maze. Unfortunately, portions of the maze have caught on fire, and
the owner of the maze neglected to create a fire escape plan. Help Joe escape
the maze.
Given Joe‘s location in the maze and which squares of the maze are on fire, you must determine whether Joe can exit the maze before the fire reaches him, and how fast he can do it.
Joe and the fire each move one square per minute, vertically or horizontally (not diagonally). The fire spreads all four directions from each square that is on fire. Joe may exit the maze from any square that borders the edge of the maze. Neither Joe nor the fire may enter a square that is occupied by a wall.
The first line of input contains a single integer, the number of test cases to follow. The first line of each test case contains the two integers R and C, separated by spaces, with 1 <= R, C<= 1000. The following R lines of the test case each contain one row of the maze. Each of these lines contains exactly C characters, and each of these characters is one of:
There will be exactly one J in each test case.
2 4 4 #### #JF# #..# #..# 3 3 ### #J. #.F
For each test case, output a single line containing IMPOSSIBLE if Joe cannot exit the maze before the fire reaches him, or an integer giving the earliest time Joe can safely exit the maze, in minutes.
3 IMPOSSIBLE
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#include <iostream>#include <cstdlib>#include <cstring>#include <cstdio>#include <algorithm>#include <string>#include <queue>#include <vector>using
namespace std;#define INF 1<<29#define eps 1e-8#define A system("pause")#define rep(i,h,n) for(int i=(h);i<=(n);i++)#define ms(a,b) memset((a),(b),sizeof(a))#define lson l,mid,rt<<1#define rson mid+1,r,rt<<1|1const
int maxn=2000+5;int
dx[]={0,1,-1,0};int
dy[]={1,0,0,-1};struct
dot{ int
x,y; bool
isfire; int
time;};int
vis[maxn][maxn];char
map[maxn][maxn];int
test,n,m;inline
bool in(dot sgx){ if(sgx.x>=0&&sgx.x<n&&sgx.y>=0&&sgx.y<m) return
true; return
false;}int
main(){ scanf("%d",&test); while(test--) { dot gx; scanf("%d%d",&n,&m); rep(i,0,n-1) scanf("%s",map[i]); queue<dot> q; while(!q.empty()) q.pop(); ms(vis,0); rep(i,0,n-1) rep(j,0,m-1) {dot F; if(map[i][j]==‘J‘) gx.x=i,gx.y=j,gx.isfire=0,gx.time=0; else
if(map[i][j]==‘F‘) vis[i][j]=1,F.x=i,F.y=j,F.isfire=1,F.time=0,q.push(F); else
if(map[i][j]==‘#‘) vis[i][j]=1; } q.push(gx); int
ret=0; while(!q.empty()) { dot next; gx=q.front(),q.pop(); rep(i,0,3) { next.x=gx.x+dx[i]; next.y=gx.y+dy[i]; next.isfire=gx.isfire;//BFS的时候注意"火势蔓延",相邻格子火势是相通的； next.time=gx.time+1; if(in(next)) { if(!vis[next.x][next.y]) vis[next.x][next.y]=1,q.push(next); } else
if(next.isfire==0) { ret=next.time;//记录当前答案； break; } } if(ret>0)break; } if(!ret) std::puts("IMPOSSIBLE"); else
printf("%d\n",ret); } //A; return
0;} |
标签：style blog class code ext color
原文地址：http://www.cnblogs.com/scottding/p/3712838.html
