给定一个 m * n 的矩阵,如果一个元素为 0,则将其所在行和列的所有元素都设为 0。请使用原地算法
https://leetcode-cn.com/problems/set-matrix-zeroes/
示例1:
示例2:
提示:
Java解法
package sj.shimmer.algorithm.m2;
import java.util.HashSet;
import java.util.Set;
import sj.shimmer.algorithm.Utils;
/**
* Created by SJ on 2021/3/4.
*/
class D39 {
public static void main(String[] args) {
int[][] matrix = {{0,1,2,0}, {3,4,5,2}, {1,3,1,5}};
setZeroes(matrix);
Utils.logArrays(matrix);
}
public static void setZeroes(int[][] matrix) {
if (matrix==null||matrix.length==0||matrix[0]==null||matrix[0].length==0) {
return;
}
Set<Integer> zeroColumn = new HashSet<>();
Set<Integer> zeroLine = new HashSet<>();
int lineLength = matrix.length;
int columnLength = matrix[0].length;
for (int i = 0; i < lineLength; i++) {
for (int j = 0; j < columnLength; j++) {
if (matrix[i][j]==0) {
zeroLine.add(i);
zeroColumn.add(j);
}
}
}
for (int i = 0; i < lineLength; i++) {
if (zeroLine.contains(i)) {
matrix[i] = new int[columnLength];
continue;
}
for (Integer integer : zeroColumn) {
matrix[i][integer] = 0;
}
}
}
}
官方解
https://leetcode-cn.com/problems/set-matrix-zeroes/solution/ju-zhen-zhi-ling-by-leetcode/
-
额外存储空间方法
- 时间复杂度:O(M×N)
- 空间复杂度:O(M+N)
-
O(1)空间的暴力