Problem description here PoisonedSwamp
You should definitely know that this is a graph search problem. You can apply either DFS or BFS. However, the main challenge is to define the state meaning the vertex/node of this graph search problem. One key observation is that, you have to take poison count into consideration while you are visiting vertices/states.
So basically 3 parameters define a state: row number(x), column number(y), poison count acquired so far after stepping into cell(x,y) since the traversal started from cell(0,0). Another thing to note that, we don’t need to take care of poison count for more than 10 because the traveler is gonna die if he acquires >= 10 poisons.
I have implemented this using queue, in fact priority queue (it is not necessary as total state space is not so high). It is possible to solve this problem by a recursive dfs too.
My code during contest: https://community.topcoder.com/stat?c=problem_solution&rm=335435&rd=18497&pm=16768&cr=23058599
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