Google编程大赛入围赛250分真题

Problem Statement

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You are given a String[] cityMap representing the layout of a city. The city

consists of blocks. The first element of cityMap represents the first row of

blocks, etc. A 'B' character indicates a location where there is a bus stop.

There will be exactly one 'X' character, indicating your location. All other

characters will be '.'. You are also given an int walkingDistance, which is the

maximum distance you are willing to walk to a bus stop. The distance should be

calculated as the number of blocks vertically plus the number of blocks

horizontally. Return the number of bus stops that are within walking distance of

your current location. Definition

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Class:

BusStops

Method:

countStops

Parameters:

String[], int

Returns:

int

Method signature:

int countStops(String[] cityMap, int walkingDistance)

(be sure your method is public)

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Constraints

cityMap will contain between 1 and 50 elements, inclusive.

Each element of cityMap will contain between 1 and 50 characters, inclusive.

Each element of cityMap will contain the same number of characters.

Each character of each element of cityMap will be 'B', 'X', or '.'.

There will be exactly one 'X' character in cityMap.

walkingDistance will be between 1 and 100, inclusive.

Examples

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{'...B.',

'.....',

'..X.B',

'.....',

'B....'}

Returns: 2

You can reach the bus stop at the top (3 units away), or on the right (2 units

away). The one in the lower left is 4 units away, which is too far. 1)

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{'B.B..',

'.....',

'B....',

'.....',

'....X'}

Returns: 3

A distance of 8 can get us anywhere on the map, so we can reach all 3 bus stops.

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{'BBBBB',

'BB.BB',

'B.X.B',

'BB.BB',

'BBBBB'}

Returns: 0

Plenty of bus stops, but unfortunately we cannot reach any of them.

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{'B..B..',

'.B...B',

'..B...',

'..B.X.',

'B.B.B.',

'.B.B.B'}

Returns: 7

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