Leetcode 细节实现 Set Matrix Zeroes

Set Matrix Zeroes

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Submissions: 58671My Submissions

Given a m x n matrix, if an element is 0, set its entire row and column to 0. Do it in place.

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题意：给定矩阵，假设矩阵的某个位置为0。则把那一行那一列的全部元素都置为0

思路：用两个bool数组，分别记录应该把全部元素置为0的行和列

复杂度：时间O(m*n)。空间O(m+n)

void setZeroes(vector<vector<int> > &matrix){
	if(matrix.empty()) return ;
	int rows = matrix.size(), columns = matrix[0].size();
	vector<bool> row(rows, false);
	vector<bool> column(columns, false);
	for(int i = 0; i < rows; ++i){
		for(int j = 0; j < columns; ++j){
			if(matrix[i][j] == 0){
				row[i] = column[j] = true;
				continue;
			}
		}
	}
	for(int i = 0; i < rows; ++i){
		if(!row[i]) continue;
		for(int j = 0; j < columns; ++j){
			matrix[i][j] = 0;
		}
	}
	for(int j = 0; j < columns; ++j){
		if(!column[j]) continue;
		for(int i = 0; i < rows; ++i){
			matrix[i][j] = 0;
		}
	}
}