矩阵中战斗力最弱的 K 行

/*
 * Similar to the previous Java solution, we count the number of soldiers in each row. 
 * The difference here is that we use Java Streams to handle the sorting and processing.
 */
import java.util.*;
import java.util.stream.*;

public class WeakestRowsStream { 
    public int[] kWeakestRows(int[][] mat, int k) { 
        return IntStream.range(0, mat.length)
            .mapToObj(i -> new int[]{(int) Arrays.stream(mat[i]).filter(x -> x == 1).count(), i})
            .sorted((a, b) -> a[0] == b[0] ? a[1] - b[1] : a[0] - b[0])
            .limit(k)
            .mapToInt(a -> a[1])
            .toArray();
    }
}