05. Breadth First Search BFS | Graph Traversal Algorithm | Concept + Implementation in C++

[@gaganb]

Two Corrections: In the range for-loop on line 32, it has to be "T nbr" not "int nbr". This is because we cannot assume the type to be int since we are abstracting it away under the template T. On line 21, the "visited" map should be "map visited" and not "map visited".

[@PrashantKumarSharma]

There are too many errors in his code. This is one of them

[@lostparadise7028]

map visited will come in bfs function instead of "map visited;"...It works same anyways,But..

[@ansumanmishra1757]

The slight change in order is because in the input(in main func) there is no edge for (0,3) . After adding an edge you will get the output as 0 1 3 2 4 5

[@josejayant94]

It worked

[@piyushbajaj8355]

yes

[@lydialarina]

I was very confused by the topic, and even though I found examples of code online, I really needed a thorough walkthrough. Excellent explanation! Thank you so much!

[@arpitkhandelwal6050]

if we are using generic programming here then why are we writing addEdge(int x, int y) instead of addEgde(t x, t y)? if we pass string to this function this will give us an error.

[@mavericmadhav]

Two issues found in this Implementation: 1) addEdge method takes int as arg type instead of Template type T. It needs to be fixed 2) addEdge for 0-3 was Missing due to which the. Order output came different than expected. Thanks for the explanation though. It was very clear.

[@praveensingh1711]

Explained well.😊 keep it up

[@ce050manankadiya7]

Nice explanation sir 👍

[@-invisibleguest-188]

theory part is good enough ,I understand it perfectly . -> but implementation part is little bit tricky and for me it was very hard to understand coz I learned it by using array in my University. -> note: i am seeing this video without maintaining the playlist may be for that it seemed confuse to me .

[@imkd4real]

I will cry u explained it so well

[@alishachhabra7995]

Very well explained!

[@rohitmathur9723]

Amazing Explanation!

[@jatinkumar4410]

nice explanation

[@joaovictormelo6442]

I would like to know if I can change t in the map visited by bool.

[@saurabhsaxena1992]

Thanks sir

[@yogeshsarowgi7599]

in line no. 32 for(int nbr : l[node]) why you are using int?? What if value is string because you make generic class

[@gouravgoel2974]

then you can use string in place of int.

[@yogeshsarowgi7599]

@@gouravgoel2974 then what is the use of generic??....it should be T

[@pratyushranjan425]

@@yogeshsarowgi7599 yepp it should be T

[@pr0mero817]

You are clouding the namespace by using namespace std. pls try the compiler trick

[@akash-lz2dq]

when you are using map for visited record then you are increasing the time complexity ,because map takes o(logn) to look up and array takes only 1 constant time ,

[@akash-lz2dq]

but if the node is of alphabatic notation or string then we cant use array thanks i got it

[@Ben-pb7ct]

Could anyone explain what is for(int nbr : l[node])? Does this mean if the integer nbr in l[node] then the loop keeps going down? and where I could find the use about this : ( please help

[@thienbinhinh7941]

you can search for "advanced loop"

[@programmer4042]

kzbin.info/www/bejne/mYSrYpejbsmLfq8

[@tombrady7390]

range-based for loop gfg

[@helloworld8912]

My code is running for infinite "if(! visited [nbr])" is not working. Please help

[@sindhumathi9209]

Can u pls explain the Find Shortest Path using BFS

[@giwrgoscy294]

THANKS MOOOOOOM

[@ishitasinghal67]

How can we print levels using this approach?

[@090-jellabharath2]

Tq sir

[@uditkotecha2636]

Nice

[@vamshisamineniz5905]

could u please put the source code in the above description

[@amitkumar_ara]

#include using namespace std; template class Graph { private: map l; public: void addEdge(int x, int y) { l[x].push_back(y); l[y].push_back(x); } void bfs(T src) { map visited; queue q; q.push(src); visited[src] = true; while (!q.empty()) { T node = q.front(); q.pop(); cout

[@binunath5525]

In line no 35 error shown that end1 was not declared in this scope

[@ashwanikumarsingh8232]

sir line no 9 me error aa raha hai error: template argument 2 is invalid

[@ayushpandey8633]

if(!visited[nbr]) its initializing also internally that too false ??? ie nbr:false

[@osiris1102]

I think that would be visited[nbr] = false;

[@sakshamp4488]

Can anyone tell me why he gas written Visited(src)=true.just not able to understand:(

[@NavneetKaur-vt8kt]

because src is the starting point of traversal, hence we mark it as true

[@tanmaychandra9434]

Sir will use of unordered_map() perform better than map() ?

[@nitinsinghrawat6891]

yes

[@nitinsinghrawat6891]

But listen in order to avoid the duplicate key in a list we use the map instead of the unordered map

[@md.salauddin]

how to get user input???

[@sagarjain4128]

we get user input by using Adjacency matrix.

[@shikharjaiswal6877]

10 | map l ; | ^~~~ BFS_Graph.cpp:3:1: note: 'std::list' is defined in header ''; did you forget to '#include '? 2 | #include +++ |+#include 3 | BFS_Graph.cpp:10:13: error: template argument 2 is invalid 10 | map l ; | ^ BFS_Graph.cpp:10:13: error: template argument 4 is invalid BFS_Graph.cpp:10:14: error: expected unqualified-id before '>' token 10 | map l ; | ^~ BFS_Graph.cpp: In member function 'void BFS_Graph::addEdge(int, int)': BFS_Graph.cpp:14:5: error: 'l' was not declared in this scope 14 | l[x].push_back(y); | ^ BFS_Graph.cpp: In member function 'void BFS_Graph::bfs(T)': BFS_Graph.cpp:21:5: error: 'queue' was not declared in this scope 21 | queue q; | ^~~~~ BFS_Graph.cpp:3:1: note: 'std::queue' is defined in header ''; did you forget to '#include '? 2 | #include +++ |+#include 3 | BFS_Graph.cpp:21:12: error: expected primary-expression before '>' token 21 | queue q; | ^ BFS_Graph.cpp:21:14: error: 'q' was not declared in this scope 21 | queue q; | ^ BFS_Graph.cpp:31:20: error: 'l' was not declared in this scope 31 | for(T nbr: l[node]){ | ^ Please help me with this errror. list in 9th line of the video is showing error.

[@lavanyabansod3433]

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