Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.
Did you use extra space?
A straight forward 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?
Code:
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class
Solution {public: void
setZeroes(vector<vector<int> > &matrix) { int
m=matrix.size(); int
n=matrix[0].size(); int
firstrow=0; int
firstcol=0; for(int
i=0;i<n;i++) if(matrix[0][i]==0){ firstrow=1; break; } for(int
j=0;j<m;j++) if(matrix[j][0]==0){ firstcol=1; break; } for(int
j=0;j<m;j++) for(int
i=0;i<n;i++){ if(matrix[j][i]==0){ matrix[j][0]=0; matrix[0][i]=0; } } for(int
i=1;i<n;i++) if(matrix[0][i]==0) for(int
j=1;j<m;j++) matrix[j][i]=0; for(int
j=1;j<m;j++) if(matrix[j][0]==0) for(int
i=1;i<n;i++) matrix[j][i]=0; if(firstrow==1) for(int
i=0;i<n;i++) matrix[0][i]=0; if(firstcol==1) for(int
j=1;j<m;j++) matrix[j][0]=0; }}; |
原文：http://www.cnblogs.com/winscoder/p/3536453.html