data/problems/262.yml
---
:id: 262
:name: Mountain Range
:url: https://projecteuler.net/problem=262
:content: "The following equation represents the _continuous_ topography of a mountainous
region, giving the <dfn title=\"height above sea level\">elevation</dfn> <var>h</var>
at any point (<var>x</var>,<var>y</var>):\n\n ![p262_formula1.gif]({{ images_dir
}}/p262_formula1.gif) \n\nA mosquito intends to fly from A(200,200) to B(1400,1400),
without leaving the area given by 0 ≤ <var>x</var>, <var>y</var> ≤ 1600.\n\nBecause
of the intervening mountains, it first rises straight up to a point A', having elevation
<var>f</var>. Then, while remaining at the same elevation <var>f</var>, it flies
around any obstacles until it arrives at a point B' directly above B.\n\nFirst,
determine <var>f<sub>min</sub></var> which is the minimum constant elevation allowing
such a trip from A to B, while remaining in the specified area. \nThen, find the
length of the shortest path between A' and B', while flying at that constant elevation
<var>f<sub>min</sub></var>.\n\nGive that length as your answer, rounded to three
decimal places.\n\n<font><u>Note</u>: For convenience, the elevation function shown
above is repeated below, in a form suitable for most programming languages:<br>\nh=(
5000-0.005*(x*x+y*y+x*y)+12.5*(x+y) ) * exp( -abs(0.000001*(x*x+y*y)-0.0015*(x+y)+0.7)
)</font>\n\n"