# Set Matrix Zeroes LeetCode Solution | Easy Approach Share:

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.length`
• `1 <= m, n <= 200`
• `-231 <= matrix[i][j] <= 231 - 1`

• 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?

Time: O(mn)
Space: O(1)

### C++

``````class Solution {
public:
void setZeroes(vector<vector<int>>& matrix) {
const int m = matrix.size();
const int n = matrix.size();
bool shouldFillFirstRow = false;
bool shouldFillFirstCol = false;

for (int j = 0; j < n; ++j)
if (matrix[j] == 0) {
shouldFillFirstRow = true;
break;
}

for (int i = 0; i < m; ++i)
if (matrix[i] == 0) {
shouldFillFirstCol = true;
break;
}

// store the information in the 1st row/col
for (int i = 1; i < m; ++i)
for (int j = 1; j < n; ++j)
if (matrix[i][j] == 0) {
matrix[i] = 0;
matrix[j] = 0;
}

// fill 0s for the matrix except the 1st row/col
for (int i = 1; i < m; ++i)
for (int j = 1; j < n; ++j)
if (matrix[i] == 0 || matrix[j] == 0)
matrix[i][j] = 0;

// fill 0s for the 1st row if needed
if (shouldFillFirstRow)
for (int j = 0; j < n; ++j)
matrix[j] = 0;

// fill 0s for the 1st col if needed
if (shouldFillFirstCol)
for (int i = 0; i < m; ++i)
matrix[i] = 0;
}
};
``````

### Java

``````class Solution {
public void setZeroes(int[][] matrix) {
final int m = matrix.length;
final int n = matrix.length;
boolean shouldFillFirstRow = false;
boolean shouldFillFirstCol = false;

for (int j = 0; j < n; ++j)
if (matrix[j] == 0) {
shouldFillFirstRow = true;
break;
}

for (int i = 0; i < m; ++i)
if (matrix[i] == 0) {
shouldFillFirstCol = true;
break;
}

// store the information in the 1st row/col
for (int i = 1; i < m; ++i)
for (int j = 1; j < n; ++j)
if (matrix[i][j] == 0) {
matrix[i] = 0;
matrix[j] = 0;
}

// fill 0s for the matrix except the 1st row/col
for (int i = 1; i < m; ++i)
for (int j = 1; j < n; ++j)
if (matrix[i] == 0 || matrix[j] == 0)
matrix[i][j] = 0;

// fill 0s for the 1st row if needed
if (shouldFillFirstRow)
for (int j = 0; j < n; ++j)
matrix[j] = 0;

// fill 0s for the 1st col if needed
if (shouldFillFirstCol)
for (int i = 0; i < m; ++i)
matrix[i] = 0;
}
}
``````

### Python

``````class Solution:
def setZeroes(self, matrix: List[List[int]]) -> None:
m = len(matrix)
n = len(matrix)
shouldFillFirstRow = 0 in matrix
shouldFillFirstCol = 0 in list(zip(*matrix))

# store the information in the 1st row/col
for i in range(1, m):
for j in range(1, n):
if matrix[i][j] == 0:
matrix[i] = 0
matrix[j] = 0

# fill 0s for the matrix except the 1st row/col
for i in range(1, m):
for j in range(1, n):
if matrix[i] == 0 or matrix[j] == 0:
matrix[i][j] = 0

# fill 0s for the 1st row if needed
if shouldFillFirstRow:
matrix =  * n

# fill 0s for the 1st col if needed
if shouldFillFirstCol:
for row in matrix:
row = 0

``````

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