[UVa] 837 - Light and Transparencies - http://kuoe0.ch/377/uva-837-light-and-transparencies/

837 - Light and Transparencies.cpp

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
using namespace std;

struct POINT  {
	int x;
	bool end;
	double c;

	bool operator< ( const POINT r ) const {
		return x < r.x;
	}
};

int toInt( char *s ) {
	int ret = 0;
	for ( int i = 0; s[ i ]; ++i )
		if ( s[ i ] != '.' )
			ret = ret * 10 + s[ i ] - '0';
	return ret;
}

POINT pt[ 10000 ];

int main() {

	int t, n;
	scanf( "%d", &t );

	while ( t-- ) {
		scanf( "%d", &n );
		char buf[ 100 ];
		for ( int i = 0; i < n; ++i ) {
			scanf( "%s", buf );
			int x1 = toInt( buf );

			scanf( "%s", buf );
			scanf( "%s", buf );
			int x2 = toInt( buf );

			scanf( "%s", buf );
			double c;
			scanf( "%lf", &c );

			if ( x1 > x2 )
				swap( x1, x2 );

			pt[ i ].x = x1, pt[ i ].end = 0, pt[ i ].c = c;
			pt[ n + i ].x = x2, pt[ n + i ].end = 1, pt[ n + i ].c = c;
		}
		sort( pt, pt + n * 2 );
		double e = 1;
		int now = pt[ 0 ].x;
		printf( "%d\n", n * 2 + 1 );
		printf( "-inf %.3lf %.3lf\n", ( double )now / 10, e );
		
		for ( int i = 0; i < n * 2; ++i ) {
			if ( now != pt[ i ].x )	
				printf( "%.3lf %.3lf %.3lf\n", ( double )now / 10, pt[ i ].x / ( double )10, e );

			if ( !pt[ i ].end )
				e *= pt[ i ].c;
			else
				e /= pt[ i ].c;
			
			now = pt[ i ].x;
		}

		printf( "%.3lf +inf %.3lf\n", ( double )now / 10, e );
		if ( t )	
			puts( "" );
	}
	return 0;
}