Зміст курсу

Breadth First Search

1. What is BFS

How to Search Graph Class Implementation

2. Practice

Breadth First Traverse Check if is One Component Shortest Path in Graph Restoring Shortest Path Find All Connected Components Is a Tree

3. Improve Your Code

Congratulations Components Methods BFT and BFS

4. Solving the Problems using BFS

Coloring Pixels Shortest Clear Path

Shortest Path in Graph

BFS searching shortest path

Well done! Now, let's implement a method that helps us to find the length of shortest path between two vertices, i. e. minimum number of edges to reach end vertice from start.

You should store the length of the way from start to curr node, and you can do it by modifying visited array: visited[i] equals:

-1, if i not visited yet
0, if i is visited as first node
1, if i is a neighbor of node, that has mark 0
k, if i is a neighbor of node with mark k-1 etc.

This way, you'll store the distance between start and current node, like at the example:

So, the answer is a visited[end].

Завдання

bfs(start, end) returns a number of edges between start and end nodes. If there is no path, return -1.

Actually this method does traverse as BFT method, but until the end vertex is found. Copy & Paste your BFT algorithm, and add some changes.

Завдання

bfs(start, end) returns a number of edges between start and end nodes. If there is no path, return -1.

Actually this method does traverse as BFT method, but until the end vertex is found. Copy & Paste your BFT algorithm, and add some changes.

Перейдіть на комп'ютер для реальної практикиПродовжуйте з того місця, де ви зупинились, використовуючи один з наведених нижче варіантів

Все було зрозуміло?

Секція 2. Розділ 3

Shortest Path in Graph

BFS searching shortest path

Well done! Now, let's implement a method that helps us to find the length of shortest path between two vertices, i. e. minimum number of edges to reach end vertice from start.

You should store the length of the way from start to curr node, and you can do it by modifying visited array: visited[i] equals:

-1, if i not visited yet
0, if i is visited as first node
1, if i is a neighbor of node, that has mark 0
k, if i is a neighbor of node with mark k-1 etc.

This way, you'll store the distance between start and current node, like at the example:

So, the answer is a visited[end].

Завдання

bfs(start, end) returns a number of edges between start and end nodes. If there is no path, return -1.

Actually this method does traverse as BFT method, but until the end vertex is found. Copy & Paste your BFT algorithm, and add some changes.

Завдання

bfs(start, end) returns a number of edges between start and end nodes. If there is no path, return -1.

Actually this method does traverse as BFT method, but until the end vertex is found. Copy & Paste your BFT algorithm, and add some changes.

Все було зрозуміло?

Секція 2. Розділ 3

Shortest Path in Graph

BFS searching shortest path

Well done! Now, let's implement a method that helps us to find the length of shortest path between two vertices, i. e. minimum number of edges to reach end vertice from start.

You should store the length of the way from start to curr node, and you can do it by modifying visited array: visited[i] equals:

-1, if i not visited yet
0, if i is visited as first node
1, if i is a neighbor of node, that has mark 0
k, if i is a neighbor of node with mark k-1 etc.

This way, you'll store the distance between start and current node, like at the example:

So, the answer is a visited[end].

Завдання

bfs(start, end) returns a number of edges between start and end nodes. If there is no path, return -1.

Actually this method does traverse as BFT method, but until the end vertex is found. Copy & Paste your BFT algorithm, and add some changes.

Завдання

bfs(start, end) returns a number of edges between start and end nodes. If there is no path, return -1.

Actually this method does traverse as BFT method, but until the end vertex is found. Copy & Paste your BFT algorithm, and add some changes.

Все було зрозуміло?

BFS searching shortest path

Well done! Now, let's implement a method that helps us to find the length of shortest path between two vertices, i. e. minimum number of edges to reach end vertice from start.

You should store the length of the way from start to curr node, and you can do it by modifying visited array: visited[i] equals:

-1, if i not visited yet
0, if i is visited as first node
1, if i is a neighbor of node, that has mark 0
k, if i is a neighbor of node with mark k-1 etc.

This way, you'll store the distance between start and current node, like at the example:

So, the answer is a visited[end].

Завдання

bfs(start, end) returns a number of edges between start and end nodes. If there is no path, return -1.

Actually this method does traverse as BFT method, but until the end vertex is found. Copy & Paste your BFT algorithm, and add some changes.

Секція 2. Розділ 3