HDOJ HDU 1026 Ignatius and the Princess I

HDOJ 1026 Ignatius and the Princess I

题目

点此查看 HDOJ 1026 Ignatius and the Princess I

分类

bfs

题意

英雄 Ignatius 救 公主 的故事背景

本题是第一部分

走迷宫 大小 n * m

迷宫构成

起点 (0, 0)

终点 (n, m)

‘.’ 空白位 可以走

‘X’ 墙 不能行走

‘数字 a’ 怪兽 Ignatius 需要在此花费 a 时间

题解

bfs求最短路 并输出过程

但是 此题不同在于打怪兽需要花费时间 节点不能同步进行

所以每一步需要记录时间信息 用优先队列决定最先需要移动的点

技巧

题目需要输出过程

倒序bfs比较方便顺序输出过程

代码

#include <iostream>
#include <cstring>
#include <queue>
#define max 110

using namespace std;

int dir[5][2] = {0,0,-1,0,1,0,0,-1,0,1};
char map[max][max];
int vis[max][max];

//结点结构体
struct pst
{
int x;
int y;
int t;
pst()
{
x = 0;
y = 0;
t = 0;
}
pst(int nx,int ny,int nt)
{
x = nx;
y = ny;
t = nt;
}
pst(const pst & b)
{
x = b.x;
y = b.y;
t = b.t;
}
bool operator < (const pst & b) const
{
if(t > b.t)
return true;
else return false;
}
//重载<用于优先队列
pst & operator = (const pst & b)
{
x = b.x;
y = b.y;
t = b.t;
return * this;
}
};

int main()
{
int m,n,nx,ny,rst,tms;
priority_queue<pst> q;
pst pn,lst;
int stx,sty,ltx,lty;
while(cin >> n >> m)
{
rst = 0;
for(int i = 0;i < n;i++)
{
for(int j = 0;j < m;j++)
cin >>  map[i][j];
}
memset(vis,0,sizeof(vis));
pst start(n-1,m-1,0);
vis[n-1][m-1] = 6;
q.push(start);
while(!q.empty())
{
lst = q.top();
//          cout << "lst " << lst.x << " " << lst.y << " " << lst.t  << " rst " << rst << endl;
if(lst.x == 0 && lst.y == 0)
{
rst = lst.t;
q.pop();
break;
}
q.pop();
for(int i = 1;i < 5;i++)
{
pn.x = lst.x + dir[i][0];
pn.y = lst.y + dir[i][1];
if(pn.x < 0 || pn.y < 0 || pn.x > n - 1|| pn.y > m - 1)
continue;
if(vis[pn.x][pn.y] || map[pn.x][pn.y] == 'X')
continue;
//              cout <<"nxy " << pn.x << " " << pn.y << endl;
vis[pn.x][pn.y] = i;
//              cout <<"vis " << vis[pn.x][pn.y] << endl;
//记录上一节点的信息
map[pn.x][pn.y] == '.' ? pn.t = lst.t + 1 : pn.t = lst.t + (map
cc68
[pn.x][pn.y] - '0') + 1;
// '.' ： 时间 + 1 | 数字 ： 时间 + 数字
q.push(pn);
}
}
//      cout << "rst " << rst << endl;
if(rst)
{
if(map[n-1][m-1] != '.' && map[n-1][m-1] != 'X' )
rst += (map[n-1][m-1] - '0');
cout << "It takes " << rst << " seconds to reach the target position, let me show you the way." << endl;
stx = 0;
sty = 0;
ltx = 0;
lty = 0;
tms = 1;
if(map[0][0] != '.' || map[0][0] != 'X' )
for(int i = 0;i < (map[0][0] - '0');i++)
cout << tms++ << "s:FIGHT AT (0,0)" << endl;
while(stx != n-1 || sty != m-1)
{
//  cout << "st " << stx << " " << sty << endl;
switch(vis[stx][sty])
{
case 1 : stx++; break;
case 2 : stx--; break;
case 3 : sty++; break;
case 4 : sty--; break;
}
cout << tms++ << "s:(" << ltx << "," << lty << ")->(" << stx << "," << sty << ")" << endl;
if(map[sty][sty] != '.')
for(int i = 0;i < (map[stx][sty] - '0');i++)
cout << tms++ << "s:FIGHT AT (" << stx << "," << sty << ")" << endl;
ltx = stx;
lty = sty;
}
cout << "FINISH" << endl;
}
else
cout << "God please help our poor hero." << endl << "FINISH" << endl;
while(!q.empty())
{
q.pop();
}
}
return 0;
}