ZOJ 1049 I Think&…

ZOJ Problem Set - 1049

I Think I Need a
Houseboat

Time Limit: 2 Seconds

Memory Limit: 65536 KB


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Fred Mapper is considering purchasing some land in Louisiana to
build his house on. In the process of investigating the land, he
learned that the state of Louisiana is actually shrinking by 50
square miles each year, due to erosion caused by the Mississippi
River. Since Fred is hoping to live in this house the rest of his
life, he needs to know if his land is going to be lost to
erosion.

After doing more research, Fred has learned that the land that is
being lost forms a semicircle. This semicircle is part of a circle
centered at (0,0), with the line that bisects the circle being the
X axis. Locations below the X axis are in the water. The semicircle
has an area of 0 at the beginning of year 1. (Semicircle
illustrated in the Figure.)


1049 I Think I Need a Houseboat" TITLE="ZOJ 1049 I Think I Need a Houseboat" />

Input Format:

The first line of input will be a positive integer indicating how
many data sets will be included (N).

Each of the next N lines will contain the X and Y Cartesian
coordinates of the land Fred is considering. These will be floating
point numbers measured in miles. The Y coordinate will be
non-negative. (0,0) will not be given.

Output Format:

For each data set, a single line of output should appear. This line
should take the form of:

��Property N: This property will begin eroding in year Z.��

Where N is the data set (counting from 1), and Z is the first year
(start from 1) this property will be within the semicircle AT THE
END OF YEAR Z. Z must be an integer.

After the last data set, this should print out ��END OF
OUTPUT.��
Notes:

1. No property will appear exactly on the semicircle boundary: it
will either be inside or outside.

2. This problem will be judged automatically. Your answer must
match exactly, including the capitalization, punctuation, and
white-space. This includes the periods at the ends of the
lines.

3. All locations are given in miles.

Sample Input:

2

1.0 1.0

25.0 0.0

Sample Output:

Property 1: This property will begin eroding in year 1.

Property 2: This property will begin eroding in year 20.

END OF OUTPUT.

Source: Mid-Atlantic USA 2001

源码：



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解题报告：属于简单题，理解题意直接写出公式求解
(x*x+y*y)*pi/2/50