[数据结构与算法]leetcode每日一题1337. 矩阵中战斗力最弱的 K 行20210801

题目

https://leetcode-cn.com/problems/the-k-weakest-rows-in-a-matrix/

答案

class Solution {
    public int[] kWeakestRows(int[][] mat, int k) {
        Map<Integer, List<Integer>> map = new HashMap<>();
            for (int i = 0; i < mat.length;i++) {
                int count = 0;
                for (int num : mat[i]) {
                    if (num == 0) {
                        break;
                    }
                    count++;
                }
                map.computeIfAbsent(count, list -> new ArrayList<>()).add(i);
            }
            List<Integer> list = new ArrayList<>();
            map.keySet().stream().sorted().forEach(row -> {
                if (list.size() == k) {
                    return;
                }
                List<Integer> rows = map.get(row);
                Collections.sort(rows);
                int remaind = k-list.size();
                for (int i = 0; i < Math.min(remaind, rows.size()); i++) {
                    list.add(rows.get(i));
                }
            });
            int[] arr = new int[k];
            for (int i = 0; i < list.size(); i++) {
                arr[i] = list.get(i);
            }
            return arr;
        
    }
}

总结

简单题一遍过。还是数据结构的考察。