[Swift]LeetCode296. 最佳开会地点 $ Best Meeting Point
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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:
- Try to solve it in one dimension first. How can this solution apply to the two dimension case?
两个或两个以上的人组成的一个小组，他们想要满足并尽量减少总的旅行距离。您将得到一个值为0或1的二维网格，其中每个1标记组中某个人的家。使用曼哈顿距离计算距离，其中距离(p1, p2) = |p2.x - p1.x| + |p2.y - p1.y|.
例如，假设有三个人生活在(0,0), (0,4)和(2,2)之间：
1 - 0 - 0 - 0 - 1 | | | | | 0 - 0 - 0 - 0 - 0 | | | | | 0 - 0 - 1 - 0 - 0
点（0,2）是一个理想的汇合点，因为2+2+2=6的总行驶距离是最小的。所以返回6。
提示：
首先试着用一维来解决它。这个解决方案如何适用于二维情况？
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 }点击：Playground测试
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