Getting maze algorithm to work on open maze - c

Question

first time using the site. I am trying to figure out how to solve a 'maze' using the shortest path. The code works for traditional mazes but the path I am trying to work on is essentially more open. When run the current path goes right, then down, then left and goes up then turns right before finally reaching B. My solution needs to go right then up then left to B. Any help would be appreciated!
9,11
xxxxxxxxxxx
x......B..x
x...xxxx..x
x...xxxx..x
x....A....x
x..xx.xx..x
x.........x
x.........x
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#define _CRT_SECURE_NO_DEPRECATE
#include <stdio.h>
#include <stdlib.h>
char** maze;
int** checked;
int rows;
int cols;
int start_row;
int start_col;
enum area
{
space,
wall,
end,
trail,
};
void alloc_maze() {
maze = malloc(rows * sizeof(char*));
for (int i = 0; i < rows; i++) {
maze[i] = malloc(cols * sizeof(char*));
}
}
void alloc_checked() {
checked = malloc(rows * sizeof(char*));
for (int i = 0; i < rows; i++) {
checked[i] = malloc(cols * sizeof(char*));
}
}
void get_maze(const char* file_name)
{
char c;
char rows_t[3] = { '\0' };
char cols_t[3] = { '\0' };
int rows_i = 0;
int cols_i = 0;
int swap = 0;
FILE* file = fopen(file_name, "r");
if (file) {
while ((c = getc(file)) != EOF) {
if (c == '\n') {
break;
} else if (c ==',')
{
swap = 1;
}
else if (!swap) {
rows_t[rows_i] = c;
rows_i++;
}
else {
cols_t[cols_i] = c;
cols_i++;
}
}
}
rows = atoi(rows_t);
cols = atoi(cols_t);
alloc_maze();
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
c = getc(file);
if (c == '\n') {
c = getc(file);
}
maze[i][j] = c;
if (c == 'A') {
start_row = i;
start_col = j;
}
}
}
fclose(file);
}
void get_checked() {
alloc_checked();
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
if (maze[i][j] == 'x') {
checked[i][j] = wall;
}
else if (maze[i][j] == 'B') {
checked[i][j] = end;
}
else {
checked[i][j] = space;
}
}
}
}
int search(int row, int col) {
int* current = &checked[row][col];
if (*current == end) {
printf("\n congrats you found the shortest path is");
return 1;
}
if (*current == space) {
*current = wall;
if (search(row, col + 1)) {
*current = trail;
printf("E");
return 1;
}
if (search(row + 1, col)) {
*current = trail;
printf("N");
return 1;
}
if (search(row - 1, col)) {
*current = trail;
printf("S");
return 1;
}
if (search(row, col - 1)) {
*current = trail;
printf("W");
return 1;
}
}
return 0;
}
void add_trail() {
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
if (maze[i][j] != 'A'){
if (checked[i][j] == trail) {
maze[i][j] = 'O';
}
}
}
}
}
void print_checked() {
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
printf("%d ", checked[i][j]);
}
printf("\n");
}
printf("\n");
}
void print_maze() {
printf("\n");
for (int i = 0; i < rows; i++) {
for (int j = 0; j < cols; j++) {
printf("%c", maze[i][j]);
}
printf("\n");
}
printf("\n");
}
int main()
{
get_maze("quickest_route_4.txt");
get_checked();
print_maze();
search(start_row, start_col);
add_trail();
print_maze();
return 0;
}

Answer 1

You have implemented a DFS - Depth First Search maze searching algorithm. This means that your searching algorithm is going to explores as far as possible along a direction before trying another one.
In your code this means that it will always try all of the options going right and then all of the options that are going down and this causes your code to not find the shortest path but just finding a path.
If you do want to find the shortest path you should implement a BFS - Breadth First Search algorithm, it will find you the shortest path since it is progressing the search in all of the active nodes at the same time. It will be a bit harder to implement though since it uses a queue data structure.
Good luck
Also notice that the path you are printing is coming out in reverse order.