最小面积矩形

/*
 * 思路：
 * 1. 使用流处理将所有点转换为字符串并存储在集合中。
 * 2. 通过嵌套流处理找到所有可能的矩形对角线对。
 * 3. 计算每个矩形的面积并找到最小值。
 */
import java.util.HashSet;
import java.util.Set;
import java.util.stream.IntStream;

public class MinRectangleAreaStream {
    public int minAreaRect(int[][] points) {
        Set<String> pointSet = new HashSet<>();
        IntStream.range(0, points.length).forEach(i -> pointSet.add(points[i][0] + "," + points[i][1]));
        return IntStream.range(0, points.length)
            .flatMap(i -> IntStream.range(i + 1, points.length)
                .filter(j -> points[i][0] != points[j][0] && points[i][1] != points[j][1] && 
                             pointSet.contains(points[i][0] + "," + points[j][1]) && 
                             pointSet.contains(points[j][0] + "," + points[i][1]))
                .map(j -> Math.abs(points[i][0] - points[j][0]) * Math.abs(points[i][1] - points[j][1])))
            .min()
            .orElse(0);
    }
}