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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?
public void setZeroes(int[][] matrix) { int m = matrix.length; int n = matrix[0].length; boolean firstrow = false; boolean firstcol = false; for(int i=0; i<m; i++) { for(int j=0; j<n; j++) { if(matrix[i][j] == 0) { if(i == 0) { firstrow = true; } if(j == 0) { firstcol = true; } else { matrix[0][j] = 0; matrix[i][0] = 0; } } } } for(int i=1; i<n; i++) { if(matrix[0][i] == 0) { for(int j=0; j<m; j++) { matrix[j][i] = 0; } } } for(int i=1; i<m; i++) { if(matrix[i][0] == 0) { for(int j=0; j<n; j++) { matrix[i][j] = 0; } } } if(firstrow) for(int i=0; i<n; i++) matrix[0][i] = 0; if(firstcol) for(int i=0; i<m; i++) matrix[i][0] = 0; }
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原文地址：http://www.cnblogs.com/linxiong/p/4294432.html
