fzu——Problem 2124 吃豆人（bfs）

本文主要是介绍fzu——Problem 2124 吃豆人（bfs），希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

 Problem Description

 Input

 Output

 Sample Input

 Sample Output

#include <iostream>
#include<cstdio>
#include<queue>
#include<cstring>
#include<cmath>
using namespace std;
char map[25][25];//地图
bool mark[25][25];//标记
int dx[] = {1,-1,0,0};
int dy[] = {0,0,1,-1};
int si,sj,ei,ej,pi,pj;
int flag;
int n,m;
struct node
{
int x,y;
double time;
bool flag;//是否获得加速
friend bool operator< (struct node a,struct node b)
{
return a.time > b.time;
}
}s,now;
priority_queue<node> lcm;
int find()//bfs找宝贝
{
int i;
if(flag == 0)
return -1;
while(!lcm.empty())
lcm.pop();
s.x = si;
s.y = sj;
s.time = 0;
lcm.push(s);
memset(mark,0,sizeof(mark));
while(!lcm.empty())
{
now = lcm.top();
lcm.pop();
for(i = 0;i < 4;i ++)
{
s = now;
s.x += dx[i];
s.y += dy[i];
if(s.x < 1 || s.y < 1 || s.x > n || s.y > m || mark[s.x][s.y] || map[s.x][s.y] == 'X')
continue;
s.time ++;
if(map[s.x][s.y] == 'S')
return s.time;
lcm.push(s);
mark[s.x][s.y] = 1;
}
}
return -1;
}
int isok()//直接伸舌头一定是最快的
{
int i;
if(s.x == ei)
{
for(i = min(s.y,ej) + 1;i < max(s.y,ej);i ++)
if(map[ei][i] == 'X')
break;
if(i == max(s.y,ej))
{
s.time += 0.2 * abs(s.y - ej);
return 1;
}
return 0;
}
if(s.y == ej)
{
for(i = min(s.x,ei) + 1;i < max(s.x,ei);i ++)
if(map[i][ej] == 'X')
break;
if(i == max(s.x,ei))
{
s.time += 0.2 * abs(s.x - ei);
return 1;
}
return 0;
}
return 0;
}
double Bfs(int a,int b,int c)
{
int i;
while(!lcm.empty())
lcm.pop();
s.x = a;
s.y = b;
s.flag = c;
s.time = 0;
memset(mark,0,sizeof(mark));
if(isok())
{
//printf("%.1lf\n",s.time);
return s.time;
}
lcm.push(s);
mark[s.x][s.y] = 1;
while(!lcm.empty())
{
now = lcm.top();
lcm.pop();
// printf("%d %d\n",now.x,now.y);
for(i = 0;i < 4;i ++)
{
s = now;
s.x += dx[i];
s.y += dy[i];
if(s.flag)
s.time += 0.5;
else
s.time += 1;
if(s.x < 1 || s.y < 1 || s.x > n || s.y > m || mark[s.x][s.y] || map[s.x][s.y] == 'X')
continue;
if(isok())
{
//printf("%.1lf\n",s.time);
return s.time;
}
if(map[s.x][s.y] == 'S')
s.flag = 1;
lcm.push(s);
mark[s.x][s.y] = 1;
}
}
return -1;
}
int main()
{
int i,j;
while(~scanf("%d%d",&n,&m))
{
flag = 0;
getchar();
for(i = 1;i <= n;i ++)
{
for(j = 1;j <= m;j ++)
{
map[i][j] = getchar();
if(map[i][j] == 'P')
{
si = i;
sj = j;
}
if(map[i][j] == 'B')
{
ei = i;
ej = j;
}
if(map[i][j] == 'S')
{
flag = 1;
pi = i;
pj = j;
}
}
getchar();
}
double ans = Bfs(si,sj,0);//直接找
int tmp = find();
if(tmp != -1)
{
double tp = Bfs(pi,pj,1);
if(tmp + tp < ans)
ans = tmp + tp;
}
printf("%.1lf\n",ans);
}
return 0;
}
/*
6 5
.S...
PXXX.
.XXX.
.XB..
.X.X.
.....
6 5
S....
PXXX.
.XXX.
.X...
.X.X.
..B..
3 3
...
PXB
XXX
3 3
P..
..B
XXX
3 3
S..
PXB
XXX
2 2
XP
B.
3 2
XP
.S
B.
4 3
SPX
..X
..X
..B
*/

这篇关于fzu——Problem 2124 吃豆人（bfs）的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！

---