zoukankan      html  css  js  c++  java
  • [LeetCode]Set Matrix Zeroes

    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.

    click to show follow up.

    Follow up:

    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 };
  • 相关阅读:
    阅读笔记第六次
    阅读笔记第五章
    阅读笔记第四章
    阅读笔记第三章
    软件需求分析课堂讨论
    阅读笔记第二篇
    阅读笔记五
    阅读笔记五
    阅读笔记三
    阅读笔记二
  • 原文地址:https://www.cnblogs.com/skycore/p/4884001.html
Copyright © 2011-2022 走看看