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题目描述:(链接)
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?
解题思路：
定义两个数组分别记录某一行或者某一列是否包含0。
1 class Solution { 2 public: 3 void setZeroes(vector<vector<int>>& matrix) { 4 int rows = matrix.size(); 5 int cols = matrix[0].size(); 6 7 vector<bool> rowsVec(rows, false); 8 vector<bool> colsVec(cols, false); 9 10 for (int i = 0; i < rows; ++i) { 11 for (int j = 0; j < cols; ++j) { 12 if (matrix[i][j] == 0) { 13 rowsVec[i] = true; 14 colsVec[j] = true; 15 continue; 16 } 17 } 18 } 19 20 for (int i = 0; i < rows; ++i) { 21 if (rowsVec[i]) { 22 fill(&matrix[i][0], &matrix[i][0] + cols, 0); 23 } 24 } 25 26 for (int j = 0; j < cols; ++j) { 27 if (colsVec[j]) { 28 for (int i = 0; i < rows; ++i) { 29 matrix[i][j] = 0; 30 } 31 } 32 } 33 } 34 };
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原文地址：http://www.cnblogs.com/skycore/p/4884001.html
