Backtracking is a general algorithm … that incrementally builds candidates to the solutions, and abandons a candidate (“backtracks”) as soon as it determines that the candidate cannot possibly be completed to a valid solution.
https://en.wikipedia.org/wiki/Backtracking
Note: This is the second part for BFS, DFS and Backtracking. The first part is here: [Leetcode for Interview]DFS, BFS, and Backtracking I.