[Swift]LeetCode296. 最佳開會地點 $ Best Meeting Point

★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★
➤微信公衆號：山青詠芝（shanqingyongzhi）
➤博客園地址：山青詠芝（https://www.cnblogs.com/strengthen/）
➤GitHub地址：https://github.com/strengthen/LeetCode
➤原文地址：http://www.javashuo.com/article/p-xynpdxro-ku.html 
➤若是連接不是山青詠芝的博客園地址，則多是爬取做者的文章。
➤原文已修改更新！強烈建議點擊原文地址閱讀！支持做者！支持原創！
★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★

A group of two or more people wants to meet and minimize the total travel distance. You are given a 2D grid of values 0 or 1, where each 1 marks the home of someone in the group. The distance is calculated using Manhattan Distance, where distance(p1, p2) = |p2.x - p1.x| + |p2.y - p1.y|.

For example, given three people living at (0,0), (0,4), and (2,2):

1 - 0 - 0 - 0 - 1
|   |   |   |   |
0 - 0 - 0 - 0 - 0
|   |   |   |   |
0 - 0 - 1 - 0 - 0

The point (0,2) is an ideal meeting point, as the total travel distance of 2+2+2=6 is minimal. So return 6.

Hint:

1. Try to solve it in one dimension first. How can this solution apply to the two dimension case?

---

兩個或兩個以上的人組成的一個小組，他們想要知足並儘可能減小總的旅行距離。您將獲得一個值爲0或1的二維網格，其中每一個1標記組中某我的的家。使用曼哈頓距離計算距離，其中距離(p1, p2) = |p2.x - p1.x| + |p2.y - p1.y|.

例如，假設有三我的生活在(0,0), (0,4)和(2,2)之間：

1 - 0 - 0 - 0 - 1
|   |   |   |   |
0 - 0 - 0 - 0 - 0
|   |   |   |   |
0 - 0 - 1 - 0 - 0

點（0,2）是一個理想的匯合點，由於2+2+2=6的總行駛距離是最小的。因此返回6。

提示：

首先試着用一維來解決它。這個解決方案如何適用於二維狀況？

---

Solution:

 1 class Solution {
 2     func minTotalDistance(_ grid:inout [[Int]]) -> Int {
 3         var rows:[Int] = [Int]()
 4         var cols:[Int] = [Int]()
 5         for i in 0..<grid.count
 6         {
 7             for j in 0..<grid[i].count
 8             {
 9                 if grid[i][j] == 1
10                 {
11                     rows.append(i)
12                     cols.append(j)
13                 }
14             }
15         }
16         cols.sort()
17         var res:Int = 0
18         var i:Int = 0
19         var j:Int = rows.count - 1
20         while(i < j)
21         {
22             res += (rows[j] - rows[i] + cols[j] - cols[i] )
23             j -= 1
24             i += 1
25         }
26         return res                
27     }
28 }

---

點擊：Playground測試

1 var sol = Solution()
2 var grid:[[Int]] = [[1,0,0,0,1],[0,0,0,0,0],[0,0,1,0,0]]
3 print(sol.minTotalDistance(&grid))
4 //Print 6