int main()
{
int graph[MAXSIZE][MAXSIZE];
struct node * hash_table[MAXSIZE] = {NULL};
int i;
int j;
int k;
int T;
int V;
int flag;
freopen("detect_cycle_graph_inp.txt", "r", stdin);
scanf("%d", &T);
for (i = 0; i < T; i++) {
scanf("%d", &V);
for (j = 1; j <= V; j++) {
make_set(hash_table, j);
for (k = 1; k <= V; k++) {
scanf("%d", &graph[j][k]);
}
}
flag = detect_cycle(graph, V, hash_table);
if (flag == 1) {
printf("Yes\n");
} else {
printf("No\n");
}
}
fclose(stdin);
return 0;
}
/** recursive function to depth first search for cycles.
* @param visit: the lock visited at this step.
* its dfs_next pointer gives the visited lock up in recursion.
* same as lookfor at level 0.
* @param level: depth of recursion. 0 is start.
* @param from: search for matches from unvisited node upwards.
*/
static void search_cycle(struct lock_ref* visit, int level,
struct lock_ref* from)
{
struct lock_ref* ref;
/* check for cycle */
if(detect_cycle(visit, from) && level != 0) {
found_cycle(visit, level);
fatal_exit("found lock order cycle");
}
/* recurse */
if(!visit->lock->visited)
from = visit;
if(verb > 1) fprintf(stderr, "[%d] visit lock %u %u %s %d\n", level,
(unsigned)visit->lock->id.thr,
(unsigned)visit->lock->id.instance,
visit->lock->create_file, visit->lock->create_line);
RBTREE_FOR(ref, struct lock_ref*, visit->lock->smaller) {
ref->lock->dfs_next = visit;
search_cycle(ref, level+1, from);
}
visit->lock->visited = 1;
}
