It offers backtracking and semantic disambiguation for parsing ambiguous grammar. Even when they terminate, parsers that use recursive descent with backtracking may require exponential time. These partial solutions are used to shortcut the backtracking recursion. Due to non-chronological backtracking, parallelization of conflict-driven clause learning is more difficult. Eight queens problem is usually solved with a backtracking algorithm. They also provide good examples for backtracking paradigm of algorithm design. Criticisms included the unusual control scheme, lack of focus on the story, and repetitive backtracking. Diagonal steps, backtracking, and stepping onto already-used squares are not allowed. This execution strategy is called chronological backtracking. The most used techniques are variants of backtracking, constraint propagation, and local search. He published a highly detailed description of a depth-first backtracking algorithm. This animation illustrates backtracking to solve the problem. Scott's algorithm was one of the first applications of a backtracking computer program. The two paradigms share many important features, like logical variables and backtracking. The third algorithm is to match the pattern against the input string by [[backtracking]].