hdu1728 逃离迷宫(bfs)
这是本人写过的最纠结的一次bfs，一看到题目就觉得比较简单，是非常基础的广搜，但是用stl写出来交上去居然WA，修改细节后一直wa，T_T，写代码能力亟须加强，有算法无代码实在是太悲剧了。。。。而且有很多细节需要注意，参考网上程序得出AC代码如下：
#include<iostream>
#include<queue>
using namespace std;
struct Node
{
int x, y;
int turn;
int dir;
};
char map[110][110];
int Go[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
int n, m;
Node start, end;
int visited[110][110];
int check(int a,int b)
{
if(a>=1&&a<=m&&b>=1&&b<=n)
return 1;
return 0;
}
int check1, limit;
queue<Node> Que;
void Bfs()
{
Node pre, next;
visited[start.x][start.y]=0;
Que.push(start);
while (!Que.empty()){
pre = Que.front();
if (pre.x == end.x && pre.y == end.y){
if (pre.turn <= limit){
check1 = 1;return ;
}
}
Que.pop();
for (int i = 0; i < 4; i ++){
next.x = pre.x + Go[i][0];
next.y = pre.y + Go[i][1];
if (check(next.x, next.y) && map[next.x][next.y] != '*'){
next.turn = pre.turn;
if (pre.dir != i){
next.turn ++;
if (next.turn > limit){
goto l;//不能用continue，暂时我还没想通
}
}
next.dir = i;
if (next.turn <= visited[next.x][next.y]){
visited[next.x][next.y] = next.turn;
Que.push(next);
}
} l:;
}
}
return ;
}
int main()
{
int t;
scanf("%d", &t);
//cin >> t;
while (t--){
scanf("%d %d", &m, &n);
//cin >> m >>n;
while (!Que.empty()){Que.pop();}
for (int i = 1; i <= m; i ++){
getchar();
for (int j = 1; j <= n; j ++){
scanf("%c", &map[i][j]);
visited[i][j]=11;
//cin >> map[i][j];
}
}
scanf("%d %d %d %d %d", &limit, &start.y, &start.x, &end.y, &end.x);
//cin >> limit >> start.y >> start.x >> end.y >> end.x ;
check1 = 0;
start.turn = start.dir = -1;
Bfs();
if (check1)printf("yes/n");
else printf("no/n");
}
return 0;
}
另外附上本人脑残的WA代码：
#include<iostream>
#include<queue>
using namespace std;
struct Node
{
int x, y;
int turn;
int dir;
};
char map[110][110];
int Go[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
int n, m;
int sx, sy, ex, ey;
int visited[110][110];
int check(int a,int b)
{
if(a>=1&&a<=m&&b>=1&&b<=n&&!visited[a][b])
return 1;
return 0;
}
int check1, limit;
void Bfs()
{
queue<Node> Que;
memset(visited, 0, sizeof(visited));
Node temp, pre, next;
temp.x = sx;
temp.y = sy;
temp.turn = -1;
temp.dir = -1;
Que.push(temp);
while (!Que.empty()){
pre = Que.front();
for (int i = 0; i < 4; i ++){
//pre.dir = i;
next.x = pre.x + Go[i][0];
next.y = pre.y + Go[i][1];
next.turn = pre.turn;
if (check(next.x, next.y) && map[next.x][next.y] != '*'){
if (next.dir != i){next.turn ++;}
if (next.turn > limit)goto l;
if (next.x == ex && next.y == ey){
if (next.turn <= limit){
//cout << next.turn<<endl;
check1 = 1;
}
return ;
}
next.dir=i;
visited[next.x][next.y] = 1;
Que.push(next);
}
l:;
}
Que.pop();
}
}
int main()
{
int t;
//scanf("%d", &t);
cin >> t;
while (t--){
//scanf("%d %d", &m, &n);
cin >> m >>n;
for (int i = 1; i <= n; i ++){
for (int j = 1; j <= m; j ++){
//scanf("%c", &map[i][j]);
cin >> map[i][j];
}
//getchar();
}
//scanf("%d %d %d %d %d", &limit, &sy, &sx, &ey, &ex);
cin >> limit >> sy >> sx >> ey >> ex ;
check1 = 0;
Bfs();
if (check1)printf("yes/n");
else printf("no/n");
}
return 0;
}