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Maximal Rectangle.txt
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Maximal Rectangle.txt
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class Solution {
public:
int maximalRectangle(vector<vector<char> > &matrix) {
// Start typing your C/C++ solution below
// DO NOT write int main() function
int nrows = matrix.size();
if (!nrows)
return 0;
int ncols = matrix[0].size();
if (!ncols)
return 0;
int height[nrows][ncols];
for (int i = 0; i < nrows; i++) {
height[i][ncols-1] = (matrix[i][ncols-1] == '1')?1:0;
for (int j = ncols - 2; j >= 0; j--)
height[i][j] = (matrix[i][j] == '1')?height[i][j+1]+1:0;
}
int l[nrows], r[nrows], mav = 0;
for (int j = 0; j < ncols; j++) {
l[0] = 0, r[nrows-1] = nrows - 1;
for (int i = 1; i < nrows; i++) {
int k = i;
while ((k > 0) && (height[i][j] <= height[k-1][j]))
k = l[k-1];
l[i] = k;
}
for (int i = nrows - 2; i >= 0; i--) {
int k = i;
while ((k < nrows - 1) && (height[i][j] <= height[k+1][j]))
k = r[k+1];
r[i] = k;
}
for (int i = 0; i < nrows; i++)
mav = max(mav, height[i][j]*(r[i]-l[i]+1));
}
return mav;
}
};