61 lines
1.8 KiB
Markdown
61 lines
1.8 KiB
Markdown
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---
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title: Lee's Algorithm
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localeTitle: 李的算法
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---
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## 李的算法
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Lee算法是迷宫路由问题的一种可能解决方案。它始终提供最佳解决方案，如果存在，但是 缓慢并需要大内存以进行密集布局。
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### 了解它是如何工作的
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该算法是基于`breadth-first`算法，它使用`queues`来存储步骤。它通常使用以下步骤：
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1. 选择一个起点并将其添加到队列中。
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2. 将有效的相邻单元添加到队列中。
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3. 从队列中删除您所在的位置并继续下一个元素。
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4. 重复步骤2和3，直到队列为空。
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### 履行
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C ++已经在`<queue>`库中实现了`<queue>` ，但如果您正在使用其他东西，欢迎您实现 你自己的队列版本。
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C ++代码：
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```c++
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int dl[] = {-1, 0, 1, 0}; // these arrays will help you travel in the 4 directions more easily
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int dc[] = {0, 1, 0, -1};
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queue<int> X, Y; // the queues used to get the positions in the matrix
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X.push(start_x); //initialize the queues with the start position
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Y.push(start_y);
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void lee()
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{
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int x, y, xx, yy;
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while(!X.empty()) // while there are still positions in the queue
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{
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x = X.front(); // set the current position
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y = Y.front();
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for(int i = 0; i < 4; i++)
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{
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xx = x + dl[i]; // travel in an adiacent cell from the current position
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yy = y + dc[i];
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if('position is valid') //here you should insert whatever conditions should apply for your position (xx, yy)
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{
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X.push(xx); // add the position to the queue
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Y.push(yy);
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mat[xx][yy] = -1; // you usually mark that you have been to this position in the matrix
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}
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}
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X.pop(); // eliminate the first position, as you have no more use for it
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Y.pop();
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}
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}
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```
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