Practicing linked list

#1


for the above question i m submitting this function but it is giving runtime error

#2

This problem is similar to finding the Nth node from the end of the linked list.

Sample Input 2 :
1 2 3 4 5 6 7 8 9 10 -1
7
5

You may assume end of the linked list as position k, ie. the point where loop begins.
Here position k is at node 7.
So 5th node from the end of linked list (assuming node 7 is the end) is 5.

Your Floyd algo for cycle detection is correct.
Error is due to the next part where you have to print the Nth node towards the head of the linked.
Dry run with this case and check that part.

#3

in he second part i m takind kth node as the last node and thn appling the same algo which we used for kth node frm end by taking n

#4

Is your doubt resolved now… or still you have any issue?

#5

runtime error is coming

#6

@ayu2321

Check now

#7

still giving run time error

#8

I checked the corrected(whose link i have shared) code on codezen.
It was running well for the sample inputs and did not give any runtime error.
Please check again. Earlier your code was not running because you did not put a break statement after a loop was detected.

#9

this is the code i am submitting

// Following is the node structure
/**************
class ListNode{
public:
int data;
ListNode* next;
};

ListNode* newListNode(int data){
ListNode *temp = new ListNode;
temp->data = data;
temp->next = NULL;
return temp;
}
***************/

ListNode* FindNode(ListNode* head, int N) {
/*Write your code here.
*Don’t write main().
*Don’t take input, it is passed as function argument.
*Don’t print output.
*Taking input and printing output is handled automatically.
*/

ListNode*slow =  head;
ListNode*fast =  head;
ListNode*temp = NULL;
ListNode*k = NULL;
if(fast == NULL && fast->next == NULL){
    return NULL;
}
while(fast != NULL && fast->next != NULL){
    fast = fast->next->next;
    slow = slow->next;
    if(fast == NULL && fast->next == NULL){
    return NULL;
	}
    if(slow == fast){
        slow = head;
        temp =  fast;
	}
    while(temp->next!=slow->next){
        temp = temp->next;
        slow = slow->next;
    }
   	k = slow->next;
    break;
}

    ListNode*slow1 =  head;
	ListNode*fast1 =  head;
    for(int i=1;i<N;i++){
        fast1 = fast1->next;
    }
    while(fast1!=k && fast1->next!=k){
        fast1 = fast1->next;
        slow1 = slow1->next; 
    }
    return slow1;

}

dbt
dbt1343×613 28.4 KB

#10

Check the code in the link i provided above.

if(slow == fast)
{
        slow = head;
        temp =  fast;
	//remove this }
    while(temp->next!=slow->next){
        temp = temp->next;
        slow = slow->next;
    }
   	k = slow->next;
    break;
}

All these lines must be within the if condition.
BECAUSE you perform these statements only when you detect a loop
#11

all test cases are not passing

dbt
dbt1316×621 33.2 KB

#12

Add a special case to check that if a node at distance N from the point where loop starts actually exists or not.
Consider
1 2 3 4 5 6 7 8 9 10 -1
7
8

Your o/p:
3

Expected output:
NULL

I added an extra condition https://ide.codingblocks.com/s/292538

#13

now also 1 test case is not passing

dbt
dbt922×519 24.9 KB

#14

Refer to the above link. That code passed all the test cases.

pp1
pp11155×794 36.5 KB

#15

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