# A tricky solution, and I wonder can this satisfy the "const place"?

• ``````class Solution {
public:
void setZeroes(vector<vector<int> > &matrix) {
int m = matrix.size();
int n = matrix[0].size();

bool line = false;
bool hine = false;

for (int i=0;i!=m;i++)
for (int j=0;j!=n;j++)
if (matrix[i][j] == 0) {
matrix[0][j] = 0;
matrix[i][0] = 0;
if (i == 0)
line = true;
if (j == 0)
hine = true;
}
for (int i=m-1;i!=0;i--)
if (matrix[i][0] == 0){
for(int j=0;j!=n;j++)
matrix[i][j] = 0;
}

for(int j=n-1;j!=0;j--)
if (matrix[0][j] == 0)
for(int k=0;k!=m;k++)
matrix[k][j] = 0;
if (matrix[0][0] == 0){
if (hine)
for (int i=0;i!=m;i++)
matrix[i][0] = 0;
if (line)
for (int j=0;j!=n;j++)
matrix[0][j] = 0;
}

}
};``````

• This post is deleted!

• Thanks for your post. However it would be better to share solution with correct code format and elaborated thoughts. Please read the Discuss FAQ for more info. Take a look at good sharing example

• This code only uses several variables. It should be considered as const space and in place.

• I don't see why you need to check if matrix[0][0] == 0 before setting the first row and first column. My code w/o the check got passed. Could you explain me about it?

• Hi, if matrix[0][0] is set to 0. It may caused by one 0 in the first col, or by one 0 in the first row, or both. So i use line and hine to distinguish the two situations.

• Actually both first row and first column are not set till the end. If matrix[0][0] == 0, we don't need to check it because first row and first column should be set to 0, and hine and line are always true. If matrix[0][0] == 1, we need help from the booleans. So we can cancel the if block and just check whether hine or line is true.

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