src/geometry/PolygonArea.h

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• Last update: 2025-07-19 20:33:24+09:00

Depends on

• src/geometry/Point.h

Code

/**
 * Author: Ulf Lundstrom
 * Date: 2009-03-21
 * License: CC0
 * Source: tinyKACTL
 * Description: Returns twice the signed area of a polygon.
 *  Clockwise enumeration gives negative area. Watch out for overflow if using int as T!
 * Status: Stress-tested and tested on kattis:polygonarea
 */
#pragma once

#include "src/geometry/Point.h"

template<class T>
T polygonArea2(vector<Point<T>>& v) {
	T a = v.back().cross(v[0]);
	rep(i,0,sz(v)-1) a += v[i].cross(v[i+1]);
	return a;
}

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/PolygonArea.h: line 10: #pragma once found in a non-first line

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