73. Set Matrix Zeroes
Given an m x n
integer matrix matrix
, if an element is 0
, set its entire row and column to 0
's.
You must do it in place.
Example 1:
Input: matrix = [[1,1,1],[1,0,1],[1,1,1]] Output: [[1,0,1],[0,0,0],[1,0,1]]
Example 2:
Input: matrix = [[0,1,2,0],[3,4,5,2],[1,3,1,5]] Output: [[0,0,0,0],[0,4,5,0],[0,3,1,0]]
Constraints:
m == matrix.length
n == matrix[0].length
1 <= m, n <= 200
-231 <= matrix[i][j] <= 231 - 1
Follow up:
- A straightforward solution using
O(mn)
space is probably a bad idea. - A simple improvement uses
O(m + n)
space, but still not the best solution. - Could you devise a constant space solution?
solution:
class Solution {
public:
void setZeroes(vector<vector<int>>& matrix) {
int rows = matrix.size();
int columns = matrix[0].size();
vector<bool>rows1(columns , 0);
vector<bool>column1(rows , 0);
queue<pair<int, int>>q;
for(int i = 0 ; i < rows ; i++)
{
for(int j =0 ; j < columns ; j++)
{
if(matrix[i][j] == 0)
q.push({i , j});
}
}
while(!q.empty())
{
pair<int, int>a = q.front();
q.pop();
int i = a.first;
int j = a.second;
if(rows1[i] == 0)
{
for(int l = 0 ; l < columns; l++)
{
matrix[i][l] = 0;
}
rows1[i] = 1;
}
if(column1[j] == 0)
{
for(int m = 0 ; m < rows ; m++)
{
matrix[m][j] = 0;
}
column1[j] = 1;
}
}
}
};
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