POJ ACM习题【No.1046】

Description

A color reduction is a mapping from a set of discrete colors to a smaller one. The solution to this problem requires that you perform just such a mapping in a standard twenty-four bit RGB color space. The input consists of a target set of sixteen RGB color values, and a collection of arbitrary RGB colors to be mapped to their closest color in the target set. For our purposes, an RGB color is defined as an ordered triple (R,G,B) where each value of the triple is an integer from 0 to 255. The distance between two colors is defined as the Euclidean distance between two three-dimensional points. That is, given two colors (R1,G1,B1) and (R2,G2,B2), their distance D is given by the equation

Input

Output

Sample Input

    0 0 0
255 255 255
0 0 1
1 1 1
128 0 0
0 128 0
128 128 0
0 0 128
126 168 9
35 86 34
133 41 193
128 0 128
0 128 128
128 128 128
255 0 0
0 1 0
0 0 0
255 255 255
253 254 255
77 79 134
81 218 0
-1 -1 -1

  

Sample Output

    (0,0,0) maps to (0,0,0)
(255,255,255) maps to (255,255,255)
(253,254,255) maps to (255,255,255)
(77,79,134) maps to (128,128,128)
(81,218,0) maps to (126,168,9)
  

此题没有什么难点，注意比对最小欧式距离时的逻辑。

    import java.util.*;

public class Main {

	public static void main(String[] args) {
		Scanner cin = new Scanner(System.in);
		String[] str;
		
		int[][] target = new int[16][3];
		int[] temp = new int[3];
		int minIndex = 0;
		double minValue = -1;
		double tempValue = 0;
		
		for(int i = 0; i < 16; i++)
		{
			str = cin.nextLine().split(" ");
			target[i][0] = Integer.valueOf(str[0]).intValue();
			target[i][1] = Integer.valueOf(str[1]).intValue();
			target[i][2] = Integer.valueOf(str[2]).intValue();
		}
		
		while(cin.hasNext())
		{
			minIndex = 0;
			minValue = -1;
			tempValue = 0;
			str = cin.nextLine().split(" ");
			temp[0] = Integer.valueOf(str[0]).intValue();
			temp[1] = Integer.valueOf(str[1]).intValue();
			temp[2] = Integer.valueOf(str[2]).intValue();
			
			if(temp[0]==-1 && temp[1]==-1 && temp[2]==-1)
				break;
			
			for(int i = 0; i < 16; i++)
			{
				tempValue = getEuclideanD(temp, target[i]);
				if(tempValue == 0)
				{
					minValue = tempValue;
					minIndex = i;
					break;
				}
				if(minValue == -1)
				{
					minValue = tempValue;
					minIndex = 0;
					continue;
				}
				if(minValue > tempValue)
				{
					minValue = tempValue;
					minIndex = i;
				}
			}
			
			System.out.println(
					"("+temp[0]+","+temp[1]+","+temp[2]+
					") maps to "+
					"("+target[minIndex][0]+","+
					target[minIndex][1]+","+
					target[minIndex][2]+")");
		}
	}
	
	private static double getEuclideanD(int[] p1, int[] p2)
	{
		double value = 0;
		
		value = Math.sqrt(Math.pow((p2[0]-p1[0]), 2) +
					Math.pow((p2[1]-p1[1]), 2) + 
					Math.pow((p2[2]-p1[2]), 2));
		
		return value;
		
	}

}

  

POJ ACM习题【No.1046】