The difference between a backtrack and a branch and a border

Question

When returning, we use both BFS and DFS. Even in branch and anchor we use bfs and dfs in addition to the least cost search.

so when we use return and when we use branch and snapping

Does using branching and snapping reduce the complexity of time?

What is the least cost search at the branch and within?

Answer 1

Rollback

• It is used to search for all possible solutions available to solve the problem.
• It moves the state-space tree using the DFS (Depth First Search) method.
• He understands that he made a bad choice and canceled the last choice by backing up.
• He searches the state tree until he finds a solution.
• It includes a feasibility function .

branches and border

• It is used to solve the optimization problem.
• It can traverse the tree in any way, DFS or BFS .
• He understands that he already has the best optimal solution, which pre-solution leads to the fact that it refuses this preliminary decision.
• He is completely looking for the state tree to get the best solution.
• It includes a restrictive function .

Answer 2

Rollback

• Backtracking is a general search algorithm for all (or some) solutions of some computational problems, in particular, the limitation of satisfaction problems, which gradually creates candidates for solutions and refuses each partial candidate c ("backtracks" ") as soon as it determines that c is not may be completed before a valid decision.
• He lists a set of partial candidates, which in principle can be implemented in various ways to give all possible solutions to this problem. Completion is carried out gradually, through a sequence of steps to expand the candidate.
• Conceptually, partial candidates are represented as nodes of a tree tree , a potential search tree. Each partial candidate is a parent of candidates that differ from him in one step of expansion, and the leaves of the tree are partial candidates that cannot be expanded further.
• It traverses this search tree recursively, from root down, in depth-first order (DFS). He understands that he made a bad choice and canceled the last choice by backing up.
• Read more: Sanjiv Bhatia Backtracking presentation for UMSL .

Branch and snap

• A algorithm with a branch and a border consists of a systematic listing of possible solutions using state space search : a set of candidate solutions is considered as forming a root tree with a complete set in the root.
• The algorithm examines the branches of this tree, which are subsets of a set of solutions. Before enumerating candidate decisions of a branch, the branch is checked for upper and lower bounds for the optimal solution and is discarded if it cannot provide a better solution than the best algorithm found so far.
• He can cross the tree in any way:
  • BFS (first breath search) or (FIFO) branch and binding
  • D-Search or (LIFO) Branch and Bound
  • Least count or (LC) search and snap
• For more information: Sanjiv Bhatia Backtracking presentation for UMSL .