Practice
Resources
Contests
Online IDE
New
Free Mock
Events New Scaler
Practice
Improve your coding skills with our resources
Contests
Compete in popular contests with top coders
Events
Attend free live masterclass hosted by top tech professionals
New
Scaler
Explore Offerings by SCALER

# Good Graph

Problem Setter: raghav_aggiwal Problem Tester: ishubansal

Problem Description

Given a directed graph of N nodes where each node is pointing to any one of the N nodes (can possibly point to itself). Ishu, the coder, is bored and he has discovered a problem out of it to keep himself busy.

The problem is as follows:

A node is 'good' if it satisfies one of the following:
1. It is the special node (marked as node 1)
2. It is pointing to the special node (node 1)
3. It is pointing to a good node.

Ishu is going to change the pointers of some nodes to make them all 'good'. You have to find the min. the number of pointers to change in order to make all the nodes good (Thus, a Good Graph).

Note: Resultant Graph should hold the property that all nodes are good and each node must point to exactly one node.

Problem Constraints
1 <= N <= 100,000

Input Format
A vector of N integers containing N numbers all between 1 to N, where i-th number is the number of node that i-th node is pointing to.

Output Format
An Integer denoting min. number of pointer changes.

Example Input
Input 1:
`A = [1, 2, 1, 2]`
Input 2:
`A = [3, 1, 3, 1]`

Example Output
Output 1:
`1`
Output 2:
`1`

Example Explanation
Explanation 1:
`Pointer of node 2 is made to point to node 1`
Explanation 2:
`Pointer of node 3 is made to point to node 1`

NOTE: You only need to implement the given function. Do not read input, instead use the arguments to the function. Do not print the output, instead return values as specified. Still have a question? Checkout Sample Codes for more details.
Hints
• Hint 1
• Complete Solution

## Discussion

Free Mock Assessment
Fill up the details for personalised experience.
Phone Number *
OTP will be sent to this number for verification
+1 *
+1
Change Number
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
*Enter the expected year of graduation if you're student
Current Employer
Company Name
College/University Name
Job Title
Job Title
Software Development Engineer (Backend)
Software Development Engineer (Frontend)
Software Development Engineer (Full Stack)
Data Scientist
Android Engineer
iOS Engineer
Devops Engineer
Support Engineer
Research Engineer
Engineering Intern
QA Engineer
Co-founder
SDET
Product Manager
Product Designer
Backend Architect
Program Manager
Release Engineer