原文鏈接：http://hi.baidu.com/linfengtingyu1/item/9f588d9edf57facfb625317d
//定義狀態常量
#define OVERFLOW -2
#define ERROR 0
#define NULL 0
#define true 1
#define TRUE 1
#define false 0
#define FALSE 0
#define STACK_INIT_SIZE 100
#define STACKINCREMENT 10
#include <stdio.h>
#include <stdlib.h>
/*
初始化迷宮,1表示通道,0表示牆
*/
int maze[8][8] = {
1,1,0,1,1,1,0,1,
1,1,0,1,1,1,0,1,
1,1,1,1,0,0,1,1,
1,0,0,0,1,1,1,1,
1,1,1,0,1,1,1,1,
1,0,1,1,1,0,1,1,
1,0,0,0,1,0,0,1,
0,1,1,1,1,1,1,1
};
//定義棧元素類型
typedef struct MStackElem
{
int x;//x座標
int y;//y座標
int val;//maze[x][y]的值
}MStackElem;
//定義棧
typedef struct {
MStackElem * base;
MStackElem * top;
int stackSize;
}MStack;
//=============Stack的實現========================
//初始化棧-------構造一個空棧
void initStack(MStack *s) {
s->base = (MStackElem *)malloc(STACK_INIT_SIZE * sizeof(MStackElem));
if (!s->base) {
printf("in initStack()...Failed to initalize the MStack ,no enough space! exit now. ");
exit(OVERFLOW);//存儲分配失敗
}
s->top = s->base;
s->stackSize = STACK_INIT_SIZE;
}
//向棧中添加元素
void push(MStack *s,MStackElem e) {
//向棧中添加元素前先判斷棧是否還有空間容納新元素
if (s->top - s->base >= s->stackSize) { //棧滿,追加元素
s->base = (MStackElem *)realloc(s->base, (STACK_INIT_SIZE+STACKINCREMENT) * sizeof(MStackElem));
if (!s->base) {
printf("in push()...Failed to realloc the MStack ,no enough space! exit now. ");
exit(OVERFLOW);//存儲分配失敗
}
s->top = s->base + s->stackSize; //重新分配空間,base的值其實已經改變,top的值也就相應的改變
s->stackSize += STACKINCREMENT;
}
//將新元素加到棧頂
*(s->top++) = e;
}
//獲得棧頂元素
MStackElem getTop(MStack *s) {
if (s->top == s->base) {
printf("in getTop(),empty stack! exit now. ");
exit(ERROR);
}
else {
return *(s->top - 1);
}
}
//刪除棧頂元素
void pop(MStack *s) {
//若棧不爲空,則刪除s的棧頂元素
if (s->top == s->base) {
printf("in pop(),empty stack! exit now. ");
exit(ERROR);
}
else {
--(s->top);
}
}
//=====================================求解迷宮的相關操作=====================//
//構造兩個棧,一個用來保存探索中的全部路徑,一個用來保存有效路徑
MStack realPath,path;
//判斷當前位置是否走過
int unPass(MStack path,MStackElem cur) {//這裏不能傳path的地址,否則在遍歷過程中它的top值就真的被改了 !!
int flag = 1;
while(path.top != path.base)
{
MStackElem e = *(path.top - 1);
if (e.x == cur.x&& e.y == cur.y)
{
flag = 0;
}
//每循環一次令頭指針下移一個位置
(path.top)--;
}
return flag;
}
//獲得東面相鄰的位置
MStackElem getEast(MStackElem cur) {
if(cur.y != 7) {//當y==7時已到了迷宮右邊界,不能再向東(右)行了
cur.y += 1;
cur.val = maze[cur.x][cur.y];
}
return cur;// 當y==7時返回的是它本身
}
//獲得南面相鄰的位置
MStackElem getSouth(MStackElem cur) {
if(cur.x != 7) {//當x==7時已到了迷宮下邊界,不能再向南(下)行了
cur.x += 1;
cur.val = maze[cur.x][cur.y];
}
return cur;// 當x==7時返回的是它本身
}
//獲得西面相鄰的位置
MStackElem getWest(MStackElem cur) {
if(cur.y != 0) {//當y==0時已到了迷宮左邊界,不能再向西(左)行了
cur.y -= 1;
cur.val = maze[cur.x][cur.y];
}
return cur;// 當y==0時返回的是它本身
}
//獲得北面相鄰的位置
MStackElem getNorth(MStackElem cur) {
if(cur.x != 0) {//當cur.x==0時表示在迷宮的上邊界,不能再向北(上)行了
cur.x -= 1;
cur.val = maze[cur.x][cur.y];
}
return cur;// 當cur.x==0時返回的還是它本身
}
//獲得下一個可通行的位置,按東南西北的方向試探
MStackElem getNext(MStackElem cur) {
MStackElem next;
next.x = next.y=next.val = -1;
if(getEast(cur).val != 0 && unPass(path,getEast(cur))) {
next = getEast(cur);
}
else if(getSouth(cur).val != 0 && unPass(path,getSouth(cur))) {
next = getSouth(cur);
}
else if(getWest(cur).val != 0 && unPass(path,getWest(cur))) {
next = getWest(cur);
}
else if(getNorth(cur).val != 0 && unPass(path,getNorth(cur))) {
next = getNorth(cur);
}
//如果當前位置的四面或爲牆或已走過,則返回的next的val值爲-1
return next;
}
//獲得迷宮路徑的函數
int getMazePath(){
MStackElem start,end,cur;
start.x = 0;
start.y = 0;
start.val = maze[start.x][start.y];
end.x = 7;
end.y = 7;
end.val = maze[end.x][end.y];
cur = start; //設定當前爲位置爲"入口位置"
do
{
if (unPass(path,cur)) {//如果當前位置未曾走到過
push(&realPath,cur);
push(&path,cur);
cur = getNext(cur);
if (cur.x == end.x && cur.y == end.y) { //到達出口了,則跳出循環,並返回true
//把出口結點放入路徑中
push(&realPath,cur);
push(&path,cur);
//直接跳出函數(而不只是跳出這個循環 )
return true;
}
else if(cur.val == -1) {//當前位置的四面或爲牆或已走過
//刪除真實路徑的棧頂元素
pop(&realPath);
cur = getTop(&realPath);//令cur指向棧頂元素
}
}
else {//如果當前位置已經走過,說明原來測試的方向不對,現在嘗試其它方向
cur = getNext(cur);
if (cur.val == -1) {//仍不通,刪除真實路徑的棧頂元素
pop(&realPath);
cur = getTop(&realPath);//令cur指向棧頂元素
}
}
} while (cur.x != end.x || cur.y != end.y);
}
//打印迷宮路徑
void printMazePath(MStack *s) {//這裏不傳MStack的地址,以防在遍歷的過程中把它們的top或base的值也修改了
MStackElem e;
while (s->base < (s->top-1)) {
e = *(s->base);//先指向棧底元素,以後依次向上增1
printf("maze[%d][%d]----->",e.x,e.y);
(s->base)++;
}
//最後一個結點沒有後繼,所以不再輸出"------>"
e = *(s->base);
printf("maze[%d][%d]",e.x,e.y);
}
main(){
//初始化棧
initStack(&realPath);
initStack(&path);
getMazePath();
printf("The path of through the maze is:\n\n");
printMazePath(&realPath);
getchar();
}