src/geometry/LineProjectionReflection.h

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• Last update: 2025-07-19 20:33:24+09:00
• Link: https://vlecomte.github.io/cp-geo.pdf

Depends on

• src/geometry/Point.h

Code

/**
 * Author: Victor Lecomte, chilli
 * Date: 2019-10-29
 * License: CC0
 * Source: https://vlecomte.github.io/cp-geo.pdf
 * Description: Projects point p onto line ab. Set refl=true to get reflection
 * of point p across line ab instead. The wrong point will be returned if P is
 * an integer point and the desired point doesn't have integer coordinates.
 * Products of three coordinates are used in intermediate steps so watch out
 * for overflow.
 * Status: stress-tested
 */
#pragma once

#include "src/geometry/Point.h"

template<class P>
P lineProj(P a, P b, P p, bool refl=false) {
	P v = b - a;
	return p - v.perp()*(1+refl)*v.cross(p-a)/v.dist2();
}

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.14.0/x64/lib/python3.14/site-packages/onlinejudge_verify/documentation/build.py", line 71, in _render_source_code_stat
    bundled_code = language.bundle(stat.path, basedir=basedir, options={'include_paths': [basedir]}).decode()
                   ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.14.0/x64/lib/python3.14/site-packages/onlinejudge_verify/languages/cplusplus.py", line 187, in bundle
    bundler.update(path)
    ~~~~~~~~~~~~~~^^^^^^
  File "/opt/hostedtoolcache/Python/3.14.0/x64/lib/python3.14/site-packages/onlinejudge_verify/languages/cplusplus_bundle.py", line 312, in update
    raise BundleErrorAt(path, i + 1, "#pragma once found in a non-first line")
onlinejudge_verify.languages.cplusplus_bundle.BundleErrorAt: src/geometry/LineProjectionReflection.h: line 13: #pragma once found in a non-first line

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