标签：bfs des str namespace algorithm main nat stream min
#include<queue>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int N = 30;
const int dx[4] = { -1, 0, 1, 0 };
const int dy[4] = { 0, -1, 0, 1 };
int n, m;
int sr, sc, er, ec;
char g[N][N];
int t[N][N][4][5];
//t[r][c][dir][col]记录到达(r,c)处且方向为dir，底面颜色为col的最短时间
struct node
{
int r, c, dir, col;//0代表绿色
};
int bfs()
{
queue<node> que;
while (!que.empty())
que.pop();
memset(t, -1, sizeof(t));
que.push({sr, sc, 0, 0});
while (!que.empty())
{
node tmp = que.front();
int r = tmp.r;
int c = tmp.c;
int dir = tmp.dir;
int col = tmp.col;
que.pop();
if (tmp.r == er && tmp.c == ec && tmp.col == 0)
return 1 + t[tmp.r][tmp.c][tmp.dir][tmp.col];
//直走
int x = r + dx[dir];
int y = c + dy[dir];
if (x >= 0 && x < n && y >= 0 && y < m && ‘#‘ != g[x][y])
{
int nextCol = (col + 1) % 5;
if (t[x][y][dir][nextCol] == -1)
{
t[x][y][dir][nextCol] = t[r][c][dir][col] + 1;
que.push({x, y, dir, nextCol});
}
}
//左右转
int nextDir = (dir + 1) % 4;
if (t[r][c][nextDir][col] == -1)
{
t[r][c][nextDir][col] = t[r][c][dir][col] + 1;
que.push({r, c, nextDir, col});
}
nextDir = ((dir - 1) % 4 + 4) % 4;
if (t[r][c][nextDir][col] == -1)
{
t[r][c][nextDir][col] = t[r][c][dir][col] + 1;
que.push({r, c, nextDir, col} );
}
}
return -1;
}
int main()
{
int kase = 0;
while (scanf("%d%d", &n, &m) == 2 && (n + m))
{
if (kase != 0)
printf("\n");
for (int i = 0; i < n; ++i)
scanf("%s", g[i]);
for (int i = 0; i < n; ++i)
for (int j = 0; j < m; ++j)
if (‘S‘ == g[i][j])
sr = i, sc = j;
else if (‘T‘ == g[i][j])
er = i, ec = j;
int ans = bfs();
printf("Case #%d\n", ++kase);
if (-1 != ans)
printf("minimum time = %d sec\n", ans);
else
printf("destination not reachable\n");
}
return 0;
}
标签：bfs des str namespace algorithm main nat stream min
原文地址：https://www.cnblogs.com/QingyuYYYYY/p/12835695.html
