【栈应用】迷宫问题

迷宫问题：给定一个迷宫的入口，找出迷宫的一条通路。

【解决办法】

1.迷宫放在一个文件里，我们将迷宫读取出来存储在一个二维数组中， 用'0'来表示通路，'1'表示不通。

2.每次探测当前位置的上下左右，如果是通路，压栈，继续探测；如果不是通路，从栈中弹出，回溯到上一个走过位置。

3.利用二维数组下标的界限来判断是否找到出口。

【代码】

1.Maze.h

#pragma once#define _CRT_SECURE_NO_WARNINGS 1#include <iostream>#include "Stack.h"using namespace std;struct Pos{Pos(int row = 0, int col = 0):_row(row), _col(col){}int _row;int _col;};void InitMazeMap(char* map, int row, int col);void PrintMazeMap(char* map, int row, int col);bool GetPath(char* map, int row, int col, Pos enter,Stack<Pos>& path);bool IsExport(const Pos& pos, int row, int col);bool IsAccess(const Pos& pos, char* map, int row, int col);void GetSize(int* prow, int* pcol);

2.Maze.cpp

<pre class="cpp" name="code">#include "Maze.h"#include <cassert>void InitMazeMap(char* map, int row, int col){FILE* f1 = fopen("MazeMap.txt", "r");assert(f1);//跳过第一行int ch = fgetc(f1);while (ch != '\n'){ch = fgetc(f1);}//开始读取迷宫地图for (int i = 0; i < row; ++i){for (int j = 0; j < col;){ch = fgetc(f1);if (ch == '0' || ch == '1'){map[i*col + j] = ch;++j;}}}fclose(f1);}void PrintMazeMap(char* map, int row, int col){for (int i = 0; i < row; ++i){for (int j = 0; j < col; ++j){cout << map[i*col + j] << " ";}cout << endl;}cout << endl;}//找通路bool GetPath(char* map, int row, int col, Pos enter, Stack<Pos>& path){map[enter._row*col + enter._col] = '2';path.Push(enter);while (!path.Empty()){Pos cur = path.Top();if (cur._col!= enter._col && cur._row!=enter._row && IsExport(cur,row,col)){return true;}//上Pos next = cur;next._row -= 1;if (IsAccess(next,map,row,col)){map[next._row*col + next._col] = '2';path.Push(next);continue;}//右next = cur;next._col += 1;if (IsAccess(next, map, row, col)){map[next._row*col + next._col] = '2';path.Push(next);continue;}//下next = cur;next._row += 1;if (IsAccess(next, map, row, col)){map[next._row*col + next._col] = '2';path.Push(next);continue;}//左next = cur;next._col -= 1;if (IsAccess(next, map, row, col)){map[next._row*col + next._col] = '2';path.Push(next);continue;}map[cur._row*col + cur._col] = '3';path.Pop();}return false;}//判断pos位置是否通bool IsAccess(const Pos& pos, char* map, int row, int col){if (pos._row >= 0 && pos._row < row&&pos._col >= 0 && pos._col < col&&map[pos._row*col + pos._col] == '0'){return true;}else{return false;}}//判断pos位置是否为出口bool IsExport(const Pos& pos, int row ,int col){if (pos._col == 0 || pos._row == 0 || pos._col == (col - 1) || pos._row == (row - 1)){return true;}else{return false;}}//从文件中获取迷宫的大小void GetSize(int* prow, int* pcol){FILE* f = fopen("MazeMap.txt", "r");assert(f);int ch = fgetc(f);while (ch != '\n' && (ch <= '0' || ch >= '9'))//跳过非数字字符{ch = fgetc(f);}while (ch >= '0'&&ch <= '9') //row{*prow = *prow * 10 + (ch - '0');ch = fgetc(f);}while (ch != '\n'&& (ch<='0' || ch>='9')){ch = fgetc(f);}while (ch >= '0' && ch <= '9')//col{*pcol = *pcol * 10 + (ch - '0');ch = fgetc(f);}fclose(f);}

3.Stack.h(这里为了复习，我将栈实现了一遍。这里可以直接用库里面的栈，就不需要自己实现了)

#pragma once#include <cassert>#include <iostream>using namespace std;template <class T>class Stack{public:Stack():_data(NULL), _size(0), _capacity(0){}~Stack(){if (_data != NULL){delete _data;_data = NULL;_size = 0;_capacity = 0;}}void Push(const T& data){CheckCapacity();_data[_size++] = data;}void Pop(){assert(_size > 0);_size--;}T& Top() const{assert(_size > 0);return _data[_size - 1];}bool Empty() const{return _size == 0;}size_t Size() const{return _size;}protected:void CheckCapacity(){if (_size == _capacity){size_t newCapacity = _capacity * 2 + 3;T* tmp = new T[newCapacity];for (size_t i = 0; i < _size; ++i){tmp[i] = _data[i];}delete _data;_data = tmp;_capacity = newCapacity;}}protected:T* _data;size_t _size;size_t _capacity;};

4.Test.cpp

#include "Stack.h"#include "Maze.h"void TestStack(){Stack<int> s1;s1.Push(1);s1.Push(2);s1.Push(3);s1.Push(4);while (!s1.Empty()){cout << s1.Top() << endl;s1.Pop();}}void TestMaze(){int row = 0;int col = 0;GetSize( &row, &col);char* Map = (char*)malloc((row*col)*sizeof(char));Pos mEnter(2, 0);Stack<Pos> path;InitMazeMap( Map, row, col);PrintMazeMap(Map, row, col);if(GetPath(Map, row, col, mEnter, path)){PrintMazeMap(Map, row, col);}else{cout << "没有通路"<<endl;}free(Map);}int main(){TestMaze();system("pause");return 0;}