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[Swift]LeetCode542. 01 矩阵 | 01 Matrix

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Given a matrix consists of 0 and 1, find the distance of the nearest 0 for each cell.

The distance between two adjacent cells is 1.

Example 1: 
Input:

0 0 0
0 1 0
0 0 0

Output:

0 0 0
0 1 0
0 0 0 

Example 2: 
Input:

0 0 0
0 1 0
1 1 1

Output:

0 0 0
0 1 0
1 2 1 

Note:

  1. The number of elements of the given matrix will not exceed 10,000.
  2. There are at least one 0 in the given matrix.
  3. The cells are adjacent in only four directions: up, down, left and right.

给定一个由 0 和 1 组成的矩阵，找出每个元素到最近的 0 的距离。

两个相邻元素间的距离为 1 。

示例 1: 
输入:

0 0 0
0 1 0
0 0 0

输出:

0 0 0
0 1 0
0 0 0

示例 2: 
输入:

0 0 0
0 1 0
1 1 1

输出:

0 0 0
0 1 0
1 2 1

注意:

  1. 给定矩阵的元素个数不超过 10000。
  2. 给定矩阵中至少有一个元素是 0。
  3. 矩阵中的元素只在四个方向上相邻: 上、下、左、右。

644ms

 1 class Solution {
 2     func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3         let n = matrix.count
 4         let m = matrix[0].count
 5         let maxDis = n + m
 6         var res: [[Int]] = Array(repeating: Array(repeating: 0, count: m), count: n)
 7             
 8         for i in 0 ..< n {
 9             for j in 0 ..< m {
10                 if matrix[i][j] == 1 {
11                     let top = (i > 0) ? res[i - 1][j] : maxDis
12                     let l = (j > 0) ? res[i][j - 1] : maxDis
13                     res[i][j] = min(maxDis, min(top, l) + 1)
14                 }
15             }
16         }
17         
18         for i in (0 ..< n).reversed() {
19             for j in (0 ..< m).reversed() {
20                 if matrix[i][j] == 1 {
21                     let bottom = (i < n - 1) ? res[i + 1][j] : maxDis 
22                     let r = (j < m - 1) ? res[i][j + 1] : maxDis
23                     res[i][j] = min(res[i][j], min(bottom, r) + 1)
24                 }
25             }
26         }
27         
28         return res
29     }
30 }
Runtime: 652 ms
Memory Usage: 20 MB
 1 class Solution {
 2     func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3         var m:Int = matrix.count
 4         var n:Int = matrix[0].count
 5         var res:[[Int]] = [[Int]](repeating:[Int](repeating:Int.max - 1,count:n),count:m)
 6         for i in 0..<m
 7         {
 8             for j in 0..<n
 9             {
10                 if matrix[i][j] == 0
11                 {
12                     res[i][j] = 0
13                 }
14                 else
15                 {
16                     if i > 0
17                     {
18                          res[i][j] = min(res[i][j], res[i - 1][j] + 1)
19                     }
20                     if j > 0
21                     {
22                         res[i][j] = min(res[i][j], res[i][j - 1] + 1)
23                     }
24                 }
25             }
26         }
27         for i in stride(from:m - 1,through:0,by:-1)
28         {
29             for j in stride(from:n - 1,through:0,by:-1)
30             {
31                 if res[i][j] != 0 && res[i][j] != 1
32                 {
33                     if i < m - 1
34                     {
35                         res[i][j] = min(res[i][j], res[i + 1][j] + 1)
36                     }
37                     if j < n - 1
38                     {
39                         res[i][j] = min(res[i][j], res[i][j + 1] + 1)
40                     }
41                 }               
42             }
43         }
44         return res
45     }
46 }

Runtime: 676 ms

Memory Usage: 20.4 MB
 1 class Solution {
 2 func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3 
 4     struct Node {
 5         var value = 0;
 6         var i = 0;
 7         var j = 0;
 8     }
 9 
10     var tempArr = matrix;
11 
12     var nodeArr = [Node]()
13     var lastNum = 0;
14     for i in 0..<matrix.count {
15         for j in 0..<matrix[i].count {
16             var node: Node = Node.init();
17             node.i = i;
18             node.j = j;
19             if matrix[i][j] == 0 {
20                 node.value = 0;
21                 nodeArr.append(node)
22             } else {
23                 node.value = -1;
24                 lastNum = lastNum + 1;
25                 tempArr[i][j] = -1;
26             }
27         }
28     }
29 
30     while lastNum > 0 {
31 
32         for k in 0..<nodeArr.count {
33             let i = nodeArr[k].i;
34             let j = nodeArr[k].j;
35             //上下左右,并且不是-1
36             if i > 0 && tempArr[i-1][j] == -1 {
37                 tempArr[i-1][j] = nodeArr[k].value + 1;
38                 let node = Node.init(value: tempArr[i-1][j], i: i-1, j: j);
39                 nodeArr.append(node);
40                 lastNum = lastNum - 1;
41             }
42             if i + 1 < tempArr.count && tempArr[i+1][j] == -1 {
43                 tempArr[i+1][j] = nodeArr[k].value + 1;
44                 let node = Node.init(value: tempArr[i+1][j], i: i+1, j: j);
45                 nodeArr.append(node);
46                 lastNum = lastNum - 1;
47             }
48             if j > 0 && tempArr[i][j-1] == -1 {
49                 tempArr[i][j-1] = nodeArr[k].value + 1;
50                 let node = Node.init(value: tempArr[i][j-1], i: i, j: j-1);
51                 nodeArr.append(node);
52                 lastNum = lastNum - 1;
53             }
54             if j + 1 < tempArr[0].count && tempArr[i][j+1] == -1 {
55                 tempArr[i][j+1] = nodeArr[k].value + 1;
56                 let node = Node.init(value: tempArr[i][j+1], i: i, j: j+1);
57                 nodeArr.append(node);
58                 lastNum = lastNum - 1;
59             }
60         }
61     }
62     return tempArr;
63   }
64 }

796ms

 1 class Solution {
 2     func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3 
 4         var matrix = matrix
 5 
 6         for row in 0..<matrix.count {
 7             for column in 0..<matrix[row].count where matrix[row][column] != 0 {                
 8                 var minDistance = Int.max - 1
 9                 
10                 //up
11                 if row > 0 {
12                     minDistance = min(minDistance, matrix[row-1][column])
13                 }     
14                   
15                 //left
16                 if column > 0 {
17                     minDistance = min(minDistance, matrix[row][column-1])
18                 }
19                 
20                 matrix[row][column] = minDistance + 1
21             }
22         }   
23         
24         
25         for row in (0..<matrix.count).reversed() {
26             for column in (0..<matrix[row].count).reversed() where matrix[row][column] != 0 {                
27                 var minDistance = matrix[row][column]
28             
29                 //down                
30                 if row < matrix.count - 1 {
31                     minDistance = min(minDistance, (matrix[row+1][column] + 1))    
32                 }
33                 
34                 //right
35                 if column < matrix[row].count - 1 {
36                     minDistance = min(minDistance, (matrix[row][column+1] + 1))
37                 }
38                 
39                 matrix[row][column] = minDistance
40             }
41         }  
42                                         
43         return matrix        
44     }
45 }

976ms

 1 class Solution {
 2     func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3         var res = matrix
 4         if matrix.count == 0 || matrix[0].count == 0 {
 5             return res
 6         }
 7         let dx = [0,0,1,-1]
 8         let dy = [1,-1,0,0]
 9         let n = matrix.count
10         let m = matrix[0].count
11         var queue = [[Int]]()
12         for i in 0 ..< n {
13             for j in 0 ..< m {
14                 if res[i][j] != 0 {
15                     res[i][j] = Int.max
16                 }else {
17                     queue.append([i, j])
18                 }
19             }
20         }
21         
22         while !queue.isEmpty {
23             let cur = queue.removeFirst()
24             for i in 0 ... 3 {
25                 let nx = dx[i] + cur[0]
26                 let ny = dy[i] + cur[1]
27                 if nx < res.count && ny < res[0].count && nx >= 0 && ny >= 0 {
28                     if res[nx][ny] > res[cur[0]][cur[1]] + 1 {
29                         res[nx][ny] = res[cur[0]][cur[1]] + 1 
30                         queue.append([nx, ny])
31                     }
32                 }
33             }
34         }
35         
36         return res
37     }
38 }

1004ms

 1 class Solution {
 2     func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3         var res = matrix
 4         if matrix.count == 0 || matrix[0].count == 0 {
 5             return res
 6         }
 7         let n = matrix.count
 8         let m = matrix[0].count
 9         var visited = [[Bool]](repeating: [Bool](repeating: false, count: m), count: n)
10         
11         for i in 0 ..< n {
12             for j in 0 ..< m {
13                 if res[i][j] == 0 {
14                     fill(&res, &visited, i, j , 0)
15                 }
16             }
17         }
18         return res
19     }
20     
21     
22     func fill(_ res: inout [[Int]], _ visited: inout [[Bool]], _ x: Int, _ y: Int, _ count :Int) {
23         visited[x][y] = true
24         let dx = [0,0,-1,1]
25         let dy = [1,-1,0,0]
26         res[x][y] = count
27         for i in 0 ... 3{
28             let nx = dx[i] + x
29             let ny = dy[i] + y
30             if nx >= 0 && ny >= 0 && nx < res.count && ny < res[0].count && res[nx][ny] != 0{
31                 if count > 1 && hasNeiborZero(res, [nx, ny]){
32                     continue
33                 }
34                 if !visited[nx][ny] || res[nx][ny] > count + 1 {
35                     fill(&res, &visited, nx, ny, count + 1)
36                 }
37             }
38         }
39         
40     }
41     func hasNeiborZero(_ maze:[[Int]], _ index:[Int]) -> Bool{
42         let x = index[0]
43         let y = index[1]
44         if x > 0 && maze[x - 1][y] == 0 {
45             return true
46         }
47         if y > 0 && maze[x][y - 1] == 0 {
48             return true
49         }
50         if y < maze[0].count - 1 && maze[x][y + 1] == 0 {
51             return true
52         }
53         if x < maze.count - 1 && maze[x + 1][y] == 0 {
54             return true
55         }
56         return false
57         
58     }
59 }

1068ms

 1 class Solution {
 2     func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3         let dirs: [(Int, Int)] = [(0, -1), (-1, 0), (1, 0), (0, 1)]
 4         let n = matrix.count
 5         let m = matrix[0].count
 6         var queue: [(Int, Int)] = []
 7         var res: [[Int]] = Array(repeating: Array(repeating: 0, count: m), count: n)
 8         
 9         for i in 0 ..< n {
10             for j in 0 ..< m {
11                 if matrix[i][j] == 0 {
12                     queue.append((i, j))
13                 } else {
14                     res[i][j] = Int.max
15                 }
16             }
17         }
18         
19         while !queue.isEmpty {
20             let curr = queue.removeFirst()
21             for d in dirs {
22                 let x = curr.0 + d.0
23                 let y = curr.1 + d.1
24                 if x < 0 || x >= n || y < 0 || y >= m || res[x][y] <= res[curr.0][curr.1] + 1 {
25                     continue
26                 }
27                 res[x][y] = res[curr.0][curr.1] + 1
28                 queue.append((x, y))
29             }
30         }
31         return res
32     }
33 }

1124ms

 1 class Solution {
 2     func updateMatrix(_ matrix: [[Int]]) -> [[Int]] {
 3         var matrix = matrix
 4         if matrix == nil || matrix.count == 0 || matrix[0] == nil || matrix[0].count == 0 {
 5             return [[Int]]()
 6         }
 7         
 8         let m = matrix.count
 9         let n = matrix[0].count
10         
11         var temp = Array(repeating:0,count:n)
12         var result = Array(repeating:temp,count:m)
13         var queue = [Point]()
14         for i in 0 ..< m{
15             for j in 0 ..< n{
16                 
17                 if matrix[i][j] == 0{
18                     result[i][j] = 0
19                     queue.append(Point(i,j,0))
20                 }else{
21                     result[i][j] = Int.max
22                 }
23             }
24         }
25         
26         
27         while !queue.isEmpty{
28             
29             
30             let point = queue.removeFirst()
31             
32             let deltaX = [0,0,1,-1]
33             let deltaY = [1,-1,0,0]
34             
35             
36             for i in 0 ..< 4 {
37                 
38                 if point.x + deltaX[i] >= 0 && point.x + deltaX[i] < m && point.y + deltaY[i] >= 0 && 
39                    point.y + deltaY[i] < n && result[point.x+deltaX[i]][point.y+deltaY[i]] == Int.max{
40                        result[point.x+deltaX[i]][point.y+deltaY[i]] = point.level + 1
41                        
42                        queue.append(Point(point.x+deltaX[i],point.y+deltaY[i],point.level+1))
43                    } 
44             }
45         }
46         
47         return result
48     }
49 }
50 
51 class Point{
52     var x = 0 
53     var y = 0 
54     var level = 0 
55     init(_ x: Int, _ y:Int, _ level:Int){
56         self.x = x
57         self.y = y
58         self.level = level
59     }
60 }

 

 

posted @ 2019-02-20 20:37  为敢技术  阅读(450)  评论(0)  编辑  收藏  举报