void removeLoop(struct node *start)
{
struct node *slow=start,*fast=start,*tmp=start;
while(tmp->link!=NULL)
{
tmp=tmp->link;
}
tmp->link=start->link->link;
if(hasLoop(start)) printf("List ha loop\n");
else printf("Doesn't contain loop\n");
while(slow&&fast&&fast->link)
{
slow=slow->link;
fast=fast->link->link;
if(slow==fast)
{
slow=start;
fast=fast->link;
while(slow->link!=fast)
{
slow=slow->link;
fast=fast->link;
}
fast->link=NULL;
}
}
if(hasLoop(start)) printf("List ha loop\n");
else printf("Doesn't contain loop\n");
}
node* unloop(node *root)
{
node *loopingNode(hasLoop(root));
if (loopingNode != NULL) {
// We found a loop
// Split the list into two parts
// one: root to loopingNode
// second: loopingNode->next to loopingNode
// count nodes in first list (root)
int rc(root->count(loopingNode));
node *preVNode(loopingNode);
loopingNode = loopingNode->nextNode();
// count second list
int lc(loopingNode->count(preVNode));
// Skip first if it is greater
SKIP_NNODES(root, rc - lc);
// skip second if it is greater and keep track of previous node
for (int c(lc - rc); c > 0; c--) {
preVNode = loopingNode;
loopingNode = loopingNode->nextNode();
}
// traverse both first and second list till they point to same node
while (loopingNode != root)
{
root = root->nextNode();
preVNode = loopingNode;
loopingNode = loopingNode->nextNode();
}
// previous node in the second list is the actual last pointer in the list
preVNode->next = NULL;
loopingNode = preVNode;
}
return loopingNode;
}
bool hasLoop(map<int, vector<int> > &table, const int &begin, vector<int> &path){
if (table.count(begin) == 0){
return false;
}
while (!table[begin].empty()){
int temp = table[begin].back();
if (find(path.begin(), path.end(), temp) != path.end()){
return true;
}
path.push_back(temp);
if (hasLoop(table, temp, path)){
return true;
}
path.pop_back();
table[begin].pop_back();
}
table.erase(begin);
return false;
}
int main(int argc, char *argv[]) {
if (argc<2) return 0;
//FILE *f = fopen(argv[1],"r");
//if (f==NULL) return 0;
char* x = argv[1];
char* tmp ;
tmp = strtok(x," ");
struct List *l;
newList(&l);
struct Entry* node;
struct Entry* n1 ;
newNode(&n1);
struct Entry* n2 ;
newNode(&n2);
struct Entry* n3 ;
newNode(&n3);
struct Entry* n4 ;
newNode(&n4);
int status = 0;
struct Entry* e = l->head;
while (tmp != (void*)0) {
if (tmp[0] == '"')
continue;
if (strcmp(tmp,"N1")==0)
node = n1;
if (strcmp(tmp,"N2")==0)
node = n2;
if (strcmp(tmp,"N3")==0)
node = n3;
if (strcmp(tmp,"N4")==0)
node = n4;
if (strcmp(tmp,"H")==0)
node = l->head;
e->next = node;
e = e->next;
tmp = strtok((void*)0," ");
}
printf(" %d",hasLoop(l));
return 0;
}
int main(int argc, char *argv[]) {
if (argc<2) return 0;
FILE *f = fopen(argv[1],"r");
if (f==NULL) return 0;
struct List *l;
newList(&l);
char x[20];
struct Entry* node;
struct Entry* n1 ;
newNode(&n1);
struct Entry* n2 ;
newNode(&n2);
struct Entry* n3 ;
newNode(&n3);
struct Entry* n4 ;
newNode(&n4);
int status = 0;
struct Entry* e = l->head;
while (fscanf(f,"%s",x)==1) {
if (x[0] == '"')
continue;
if (strcmp(x,"N1")==0)
node = n1;
if (strcmp(x,"N2")==0)
node = n2;
if (strcmp(x,"N3")==0)
node = n3;
if (strcmp(x,"N4")==0)
node = n4;
if (strcmp(x,"H")==0)
node = l->head;
e->next = node;
e = e->next;
}
fclose(f);
printf(" %d",hasLoop(l));
return 0;
}
bool canFinish(int numCourses, vector<vector<int>>& prerequisites) {
if (numCourses == 0 || numCourses == 1){
return true;
}
if (prerequisites.size() == 0){
return true;
}
map<int, vector<int> > m;
for (auto &i : prerequisites){
m[i[0]].push_back(i[1]);
}
vector<int> path;
while (!m.empty()){
auto it = m.begin();
path.push_back(it->first);
if (hasLoop(m, it->first, path)){
return false;
}
path.pop_back();
}
return true;
}
