zoukankan      html  css  js  c++  java
  • 885. Spiral Matrix III

    On a 2 dimensional grid with R rows and C columns, we start at (r0, c0) facing east.

    Here, the north-west corner of the grid is at the first row and column, and the south-east corner of the grid is at the last row and column.

    Now, we walk in a clockwise spiral shape to visit every position in this grid. 

    Whenever we would move outside the boundary of the grid, we continue our walk outside the grid (but may return to the grid boundary later.) 

    Eventually, we reach all R * C spaces of the grid.

    Return a list of coordinates representing the positions of the grid in the order they were visited.

    Example 1:

    Input: R = 1, C = 4, r0 = 0, c0 = 0
    Output: [[0,0],[0,1],[0,2],[0,3]]
    
    
    

    Example 2:

    Input: R = 5, C = 6, r0 = 1, c0 = 4
    Output: [[1,4],[1,5],[2,5],[2,4],[2,3],[1,3],[0,3],[0,4],[0,5],[3,5],[3,4],[3,3],[3,2],[2,2],[1,2],[0,2],[4,5],[4,4],[4,3],[4,2],[4,1],[3,1],[2,1],[1,1],[0,1],[4,0],[3,0],[2,0],[1,0],[0,0]]
    
    
    

    Note:

    1. 1 <= R <= 100
    2. 1 <= C <= 100
    3. 0 <= r0 < R
    4. 0 <= c0 < C

    解法:过程模拟
    class Solution {
    public:
        vector<vector<int>> spiralMatrixIII(int R, int C, int r0, int c0) {
            vector<vector<int>> res;
            int left=c0,right=c0,top=r0,bottom=r0;
            res.push_back({r0,c0});
            int cnt=-1;
            while(left>=0||right<=C-1||top>=0||bottom<=R-1){
                cnt++;
                if(cnt%4==0){
                    right=right+1;
                    if(top<0)
                        continue;
                    for(int j=max(left+1,0);j<=min(right,C-1);j++)
                        res.push_back({top,j});
                }
                if(cnt%4==1){
                    bottom=bottom+1;
                    if(right>C-1)
                        continue;
                    for(int i=max(top+1,0);i<=min(bottom,R-1);i++)
                        res.push_back({i,right});
                }
                if(cnt%4==2){
                    left=left-1;
                    if(bottom>R-1)
                        continue;
                    for(int j=min(right-1,C-1);j>=max(left,0);j--)
                        res.push_back({bottom,j});
    
                }
                if(cnt%4==3) {
                    top=top-1;
                    if(left<0)
                        continue;
                    for (int i = min(bottom-1,R-1); i >= max(top,0); i--)
                        res.push_back({i, left});
    
                }
            }
            return res;
        }
    };
  • 相关阅读:
    关于指针的定义格式
    C# 调用Qt编写的控件
    Qt中的泛型容器
    Qt之自定义属性Q_PROPERTY
    QT——键盘事件(捕获按键事件)
    Qt 嵌入浏览器 QWebEngineView实现浏览器基本功能
    QT TextEdit 自适应窗口大小,填满窗口 ——基于 函数
    为什么用QWebEngineView开发的浏览器速度很慢
    Qt5.9使用QWebEngineView加载网页速度非常慢,问题解决
    QJson QxORM QtWebApp TreeFrog
  • 原文地址:https://www.cnblogs.com/learning-c/p/9764062.html
Copyright © 2011-2022 走看看