The Challenge of River Crossing
What was the challenge?
Let's name five men as M1, M2, M3, M4, M5 & five dogs as D1, D2, D3, D4, D5.
Assume D1 be the dog having advanced skills of operating boat.
TRAVEL CHART :
1] The dog D1 rows D2, D3 across the river and returns back. After returning back D1 takes D4 across the river & returns back once again.
START : D1-M1, D5-M5, M2, M3, M4 DESTINATION : D2, D3, D4
2] Now, M2, M3 and M4 cross river.
START : D1-M1, D1-M5 DESTINATION : D2-M2, D3-M3, D4-M4
3] Someone from DESTINATION needs to return back to allow others at START to cross the river. So, D4-M4 returns and D1-M1 cross the river.
START : D4-M4, D5-M5 DESTINATION : D1-M1, D2-M2, D3-M3
4] After D1-M1 reaches to the DESTINATION, D3-M3 returns back.
START : D3-M3, D4-M4, D5-M5 DESTINATION : D1-M1, D2-M2
5] Now, M3, M4 and M5 cross the river.
START : D3, D4, D5 DESTINATION : D1-M1, D2-M2, M3, M4, M5.
6] Finally, the dog D1 at the DESTINATION returns back and makes 2 trips to take D3, D4 and D5 across the river.
START : None DESTINATION : D1-M1, D2-M2, D3-M3, D4-M4, D5-M5.
This way, five men and five dog cross the river successfully.
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