# I have Graph-phobia. How do I overcome it?

I always try to ignore graph related questions during contests. But I want to overcome this fear of graphs. What should I do? From where should I start? and is it good to copy paste ready made graph functions from internet (like bfs,dijkstra) and use in my code?

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First read about traversal ie BFS and DFS.And then try to implement it yourself.

also whenever you are solving graph problem try to use C++ STL(for EX. vector).,they will help you in implementing graph very fast.

For BFS & DFS watch this video http://www.youtube.com/watch?v=zLZhSSXAwxI and think how you can implement them(Hint:make good use of queue, stack and pair from STL).

When you are done with traversal its time to apply them.

Try to solve http://www.spoj.com/problems/PPATH/ using DFS.

and for BFS here solve this http://www.spoj.com/problems/CAM5/ .

here few more easy problem which you can solve using only BFS and DFS. http://www.codechef.com/JUNE14/problems/DIGJUMP
http://www.spoj.com/problems/PRATA/
http://www.spoj.com/problems/ONEZERO/
http://www.spoj.com/problems/PPATH/
http://www.spoj.com/problems/HERDING/
http://www.spoj.com/problems/PT07Z/
http://www.spoj.com/problems/NICEBTRE/
http://www.spoj.com/problems/CERC07K/
http://www.spoj.com/problems/BUGLIFE/
http://www.spoj.com/problems/COMCB/
http://www.spoj.com/problems/NAKANJ/
http://www.codechef.com/IOPC2013/problems/IOPC13N/
http://www.codechef.com/IOPC2013/problems/IOPC13G/
http://www.codechef.com/IOPC2013/problems/IOPC13C

Note: only after solving these problem proceed to other algorithm like dijsktra,prims,maxflow etc. because they will be lot easier then.

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try this one:

It is a good question and requires knowledge of only bfs or dfs.

nice collection of graph problems…
there’s a lot of graph probs on uva hunting.Many of those are for beginners.

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