auto-timetabling

gistfile1.txt

#include <string.h>
#include <stdio.h>

/* 
x-axis: time id
y-axis: teacher/course id
    0   1   2 
  -----------
0 | 1   1  -1 
1 | 1   1   1 
2 |-1  -1   1 

*/

#define Y 3
#define X 3
int priority[Y][X] = {
    1,  1,  -1,
    1,  1,  1,
    -1, -1, 1
};
int result[Y][X];

void output() {
    for (int j = 0; j < Y; ++j) {
        for (int i = 0; i < X; ++i) {
            printf("%d", result[j][i]);
            if (i != X - 1) {
                printf(" ");
            }
        }
        printf("\n");
    }
}

bool noconflict(int y, int x) {
    // it is non-available time.
    if (priority[y][x] == -1) {
        return false;
    }

    // it is available time.
    // is it confilct with previous decisions?
    for (int j = 0; j < y; ++j) {
        if (result[j][x] == 1) {
            return false;
        }
    }

    // ok.
    return true;
}

void search(int y) {
    if (y == 3) {
        printf("get a result.\n");
        output();
        return;
    }

    for (int x = 0; x < X; ++x) {
        if (noconflict(y, x)) {
            // place.
            result[y][x] = 1;
            search(y+1);
            // un-place
            result[y][x] = 0;
        }
    }
}

int main(int argc, char* argv[]) {
    search(0);
}