Salt Lake City looks like a rectangle crossed with M streets going from North to South and with N streets going from East to West. The city is frequented by tourists who are suppose to ride around in the busses. The Utah governor wants to controll all moves of the busses. He plans to put policemen at some intersections to watch all the busses moving on the streets visible from that intersections. What is the minimum number of policemen needed for the bus watch?
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Best Answer k-man, 03 March 2013 - 02:09 AM
Spoiler for assuming that a policeman can see as far the street goes...
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7 replies to this topic
#3
k-man
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Posted 03 March 2013 - 02:09 AM Best Answer
Spoiler for assuming that a policeman can see as far the street goes...
#4
phil1882
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Posted 03 March 2013 - 04:59 AM
one policeman needs to see each horizontal and vertical street.
Spoiler for
Edited by phil1882, 03 March 2013 - 05:00 AM.
#5
bonanova
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Posted 08 March 2013 - 03:55 AM
Spoiler for assuming that a policeman can see as far the street goes...
Does this ensure they can see all the busses, or just all the intersections?
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#6
k-man
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Posted 08 March 2013 - 04:17 PM
Spoiler for assuming that a policeman can see as far the street goes...
Does this ensure they can see all the busses, or just all the intersections?
Spoiler for
#8
Krishna Kutty
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Posted 08 March 2013 - 05:58 PM
I think this might be right.
Suppose M<N.
Then, keeping one policeman each at the junctions along the diagonal of a square of side M will take care of M number of streets.
And N-M policemen are required who can stand at any point on streets from east to west which does not belong to the M*M square.
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