Isoceles | Topcoder Archive

Problem Statement

Given a list of points return how many unique isoceles right triangles use 3 of those points as corners. An isoceles right triangle has 2 sides of equal length and a single right angle (90 degrees). Two isoceles triangles are unique if they differ by at least one point.

Definition

Class:: Isoceles
Method:: howMany
Parameters:: int[], int[]
Returns:: int
Method signature:: int howMany(int[] xs, int[] ys)
(be sure your method is public)

Notes

xs[K] is the x-coordinate of the Kth point and ys[K] is the y-coordinate of the Kth point

Constraints

xs will contain between 3 and 50 elements inclusive
ys will contain between 3 and 50 elements inclusive
xs and ys will contain the same number of elements
Each element of xs will be between -1000000 and 1000000 inclusive
Each element of ys will be between -1000000 and 1000000 inclusive
There will be no duplicate points

Examples

```
{0,1,2}
```
```
{0,10,0}
```
```
Returns: 0
```
```
{0,0,5,5}
```
```
{0,5,0,5}
```
```
Returns: 4
```
There are four right isoceles triangles in a square.

{-1000000,1000000,0}

{0,0,1000000}

Returns: 1

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