Way to calculate Distance between two Points

[fengyuanyang]

Description
Give two points(x, y),
need a way to get distances

Given 4 parameters (x1, y1, x2, y2)
When x1 = 0, y1 = 0, x2 = 1, y2 = 0
Expect return 1;

When x1 = 0, y1 = 0, x2 = 0, y2 = 1
Expect return 1;

When x1 = 0, y1 = 0, x2 = 1, y2 = 1
Expect return Math.sqrt(2);

When x1 = 3, y1 = 2, x2 = 7, y2 = 7
Expect return Math.sqrt(41);

When x1 = -3, y1 = -2, x2 = 7, y2 = 7
Expect return Math.sqrt(181);

Additional context

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Important Checklist

• I have written unit test first, make it red(fail first).
• I have then written logic code, make it green(success)
• I have tried to refactor my code, make it understandable(document my code)