add Path library
add priority queue implementation
add dictionary implementation
finish function to check path between two positions given human position
finish function to find rescue solution (still bug)
bug fix: get wrong number of rows and columns
bug fix: add condition in isSubGoal function
fix bug: change the subGoal criteria
finished findSolution function but still cannot find the optimal solution
improve findSolution function (still bug)
bug fix: infinitive function call when there is no solution in findSolution function