Description
定义一个二维数组：
int maze[5][5] = {
0, 1, 0, 0, 0,
0, 1, 0, 1, 0,
0, 0, 0, 0, 0,
0, 1, 1, 1, 0,
0, 0, 0, 1, 0,
};
它表示一个迷宫，其中的1表示墙壁，0表示可以走的路，只能横着走或竖着走，不能斜着走，要求编程序找出从左上角到右下角的最短路线。
Input
一个5 × 5的二维数组，表示一个迷宫。数据保证有唯一解。Output
左上角到右下角的最短路径，格式如样例所示。Sample Input
0 1 0 0 0
0 1 0 1 0
0 0 0 0 0
0 1 1 1 0
0 0 0 1 0
Sample Output
(0, 0)
(1, 0)
(2, 0)
(2, 1)
(2, 2)
(2, 3)
(2, 4)
(3, 4)
(4, 4)
BFS、DFS都可以
1.BFS：用树存路径压入栈，一次AC看代码吧：
//AC:736K 0MS
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cstdio>
#include<cmath>
#include<stack>
#include<queue>
using namespace std;
struct map{
int x,y;
int parent;
int step;
}path[1000],S;
bool vis[5][5];
void BFS(int s[5][5]){
map now,next;
memset(vis,false,sizeof(vis));
now.x=0,now.y=0,now.step=0;
path[0].x=0,path[0].y=0;
int n=1,m=-1;
vis[0][0]=true;
queue<map>Q;
stack<map>N;
Q.push(now);
while(!Q.empty()){
now=Q.front();
Q.pop();
m++;
if(now.x==4&&now.y==4){
N.push(path[m]);
for(;;){
m=path[m].parent;
N.push(path[m]);
if(m==0)
break;
}
for(int i=0;i<=now.step;i++){
S=N.top();
N.pop();
printf("(%d, %d)\n",S.x,S.y);
}
return;
}
for(int j=1;j<=4;j++){
if(j==1){
next.x=now.x;
next.y=now.y+1;
next.step=now.step+1;
if(!vis[next.x][next.y]&&0<=next.x&&next.x<=4&&0<=next.y&&next.y<=4&&s[next.x][next.y]!=1){
Q.push(next);
path[n].x=next.x;
path[n].y=next.y;
path[n].parent=m;
n++;
}
}
if(j==2){
next.x=now.x+1;
next.y=now.y;
next.step=now.step+1;
if(!vis[next.x][next.y]&&0<=next.x&&next.x<=4&&0<=next.y&&next.y<=4&&s[next.x][next.y]!=1){
Q.push(next);
path[n].x=next.x;
path[n].y=next.y;
path[n].parent=m;
n++;
}
}
if(j==3){
next.x=now.x-1;
next.y=now.y;
next.step=now.step+1;
if(!vis[next.x][next.y]&&0<=next.x&&next.x<=4&&0<=next.y&&next.y<=4&&s[next.x][next.y]!=1){
Q.push(next);
path[n].x=next.x;
path[n].y=next.y;
path[n].parent=m;
n++;
}
}
if(j==4){
next.x=now.x;
next.y=now.y-1;
next.step=now.step+1;
if(!vis[next.x][next.y]&&0<=next.x&&next.x<=4&&0<=next.y&&next.y<=4&&s[next.x][next.y]!=1){
Q.push(next);
path[n].x=next.x;
path[n].y=next.y;
path[n].parent=m;
n++;
}
}
}
}
}
int main(){
int maze[5][5];
for(int i=0;i<5;i++)
for(int j=0;j<5;j++)
scanf("%d",&maze[i][j]);
BFS(maze);
return 0;
}2.DFS，这个写的时候由于每种情况分开写bug一大堆：
//AC: 708K 0MS
#include<cstdio>
#include<iostream>
#include<cstring>
#include<stack>
using namespace std;
bool vis[5][5];
struct{
int x,y;
}path[1000];
int n=0;
void DFS(int s[5][5],int x,int y,int step){
vis[path[step].x][path[step].y]=true;
for(int i=1;i<=4;i++){
if(i==1){
path[step+1].x=x+1;
path[step+1].y=y;
if(0<=path[step+1].x&&path[step+1].x<=4&&0<=path[step+1].y&&path[step+1].y<=4&&s[path[step+1].x][path[step+1].y]!=1&&!vis[path[step+1].x][path[step+1].y]){
if(path[step+1].x==4&&path[step+1].y==4){
n=step;
}
if(n) return;
else{
DFS(s,path[step+1].x,path[step+1].y,step+1);
if(n) break;
vis[path[step+1].x][path[step+1].y]=false;
}
}
}
if(i==2){
path[step+1].x=x;
path[step+1].y=y+1;
if(0<=path[step+1].x&&path[step+1].x<=4&&0<=path[step+1].y&&path[step+1].y<=4&&s[path[step+1].x][path[step+1].y]!=1&&!vis[path[step+1].x][path[step+1].y]){
if(path[step+1].x==4&&path[step+1].y==4){
n=step+1;
}
if(n) return;
else{
DFS(s,path[step+1].x,path[step+1].y,step+1);
if(n) break;
vis[path[step+1].x][path[step+1].y]=false;
}
}
}
if(i==3){
path[step+1].x=x-1;
path[step+1].y=y;
if(0<=path[step+1].x&&path[step+1].x<=4&&0<=path[step+1].y&&path[step+1].y<=4&&s[path[step+1].x][path[step+1].y]!=1&&!vis[path[step+1].x][path[step+1].y]){
if(path[step+1].x==4&&path[step+1].y==4){
n=step+1;
}
if(n) return;
else{
DFS(s,path[step+1].x,path[step+1].y,step+1);
if(n) break;
vis[path[step+1].x][path[step+1].y]=false;
}
}
}
if(i==4){
path[step+1].x=x;
path[step+1].y=y-1;
if(0<=path[step+1].x&&path[step+1].x<=4&&0<=path[step+1].y&&path[step+1].y<=4&&s[path[step+1].x][path[step+1].y]!=1&&!vis[path[step+1].x][path[step+1].y]){
if(path[step+1].x==4&&path[step+1].y==4){
n=step+1;
}
if(n) return;
else{
DFS(s,path[step+1].x,path[step+1].y,step+1);
if(n) break;
vis[path[step+1].x][path[step+1].y]=false;
}
}
}
}
}
int main(){
int maze[5][5];
memset(vis,false,sizeof(vis));
for(int i=0;i<5;i++)
for(int j=0;j<5;j++)
scanf("%d",&maze[i][j]);
DFS(maze,0,0,0);
for(int i=0;i<=n+1;i++)
printf("(%d, %d)\n",path[i].x,path[i].y);
return 0;
}
