[Swift]LeetCode885. 螺旋矩陣 III | Spiral Matrix III

時間 2019-11-11

標籤 swift leetcode885 leetcode 螺旋矩陣 iii spiral matrix 欄目 Swift 简体版

原文原文鏈接

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➤微信公衆號：山青詠芝（shanqingyongzhi）
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➤GitHub地址：https://github.com/strengthen/LeetCode
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On a 2 dimensional grid with R rows and C columns, we start at (r0, c0) facing east.git

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.github

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

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.) app

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

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

Example 1:spa

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

Example 2:code

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:htm

1 <= R <= 100
1 <= C <= 100
0 <= r0 < R
0 <= c0 < C

在 R 行 C 列的矩陣上，咱們從 (r0, c0) 面朝東面開始

這裏，網格的西北角位於第一行第一列，網格的東南角位於最後一行最後一列。

如今，咱們以順時針按螺旋狀行走，訪問此網格中的每一個位置。

每當咱們移動到網格的邊界以外時，咱們會繼續在網格以外行走（但稍後可能會返回到網格邊界）。

最終，咱們到過網格的全部 R * C 個空間。

按照訪問順序返回表示網格位置的座標列表。

示例 1：

輸入：R = 1, C = 4, r0 = 0, c0 = 0
輸出：[[0,0],[0,1],[0,2],[0,3]]

示例 2：

輸入：R = 5, C = 6, r0 = 1, c0 = 4
輸出：[[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]]

提示：

1 <= R <= 100
1 <= C <= 100
0 <= r0 < R
0 <= c0 < C

Runtime: 128 ms

Memory Usage: 19.7 MB

 1 class Solution {
 2     func spiralMatrixIII(_ R: Int, _ C: Int, _ r0: Int, _ c0: Int) -> [[Int]] {
 3         var r = r0
 4         var c = c0
 5         var res:[[Int]] = [[Int]](repeating:[Int](repeating:0,count:2),count:R * C)
 6         res[0] = [r, c]
 7         var x:Int = 0
 8         var y:Int = 1
 9         var n:Int = 0
10         var i:Int = 0
11         var tmp:Int = 0
12         var j:Int = 1
13         while (j < R * C)
14         {
15             r += x
16             c += y
17             i += 1
18             if 0 <= r && r < R && 0 <= c && c < C
19             {
20                 res[j] = [r, c]
21                 j += 1
22             }
23             if i == (n / 2 + 1)
24             {
25                 i = 0
26                 n += 1 
27                 tmp = x
28                 x = y
29                 y = -tmp
30             }
31         }
32         return res
33     }
34 }

128ms

 1 class Solution {
 2     func spiralMatrixIII(_ R: Int, _ C: Int, _ r0: Int, _ c0: Int) -> [[Int]] {
 3         var result = [[Int]]()
 4         var i = r0
 5         var j = c0
 6         var currentLevel = 1
 7         self.appendResultIfInMatrix(&result,i,j,R,C) //adding first element
 8         while true {
 9             for _ in 1 ... currentLevel {
10                 j += 1
11                 self.appendResultIfInMatrix(&result,i,j,R,C)
12             }
13             if result.count == R*C {
14                 break
15             }
16             for _ in 1 ... currentLevel {
17                 i += 1
18                 self.appendResultIfInMatrix(&result,i,j,R,C)
19             }
20             if result.count == R*C {
21                 break
22             }
23             currentLevel += 1
24             for _ in 1 ... currentLevel {
25                 j -= 1
26                 self.appendResultIfInMatrix(&result,i,j,R,C)
27             }
28             if result.count == R*C {
29                 break
30             }
31             for _ in 1 ... currentLevel {
32                 i -= 1
33                 self.appendResultIfInMatrix(&result,i,j,R,C)
34             }
35             if result.count == R*C {
36                 break
37             }
38             currentLevel += 1
39         }
40         return result
41     }
42     
43     func appendResultIfInMatrix(_ result: inout [[Int]], _ i:Int, _ j:Int, _ R:Int, _ C: Int) {
44         if self.inMatrix(i,j,R,C) {
45             result.append([i,j])
46         }
47     }
48     
49     func inMatrix(_ i:Int, _ j:Int, _ R:Int, _ C: Int) -> Bool {
50         if i >= 0 && i < R && j >= 0 && j < C {
51             return true
52         } else {
53             return false
54         }
55     }
56 }

140ms

 1 class Solution {
 2     //first: true for row, false for col; second: true forward, false backward
 3     private let op = [(true,1),(false,1),(true,-1),(false,-1)] 
 4     private var ans = [[Int]]()
 5     private var current = [Int]()
 6     var visited = 1
 7     
 8     func spiralMatrixIII(_ R: Int, _ C: Int, _ r0: Int, _ c0: Int) -> [[Int]] {
 9         var step = 1; var turningCount = 0
10         self.visited = 1
11         self.current = [r0,c0]
12         self.ans = [current]
13         let total = R*C
14         
15         while (visited != total) {
16             let turningSignal = op[turningCount%4]
17             move(turningSignal.0, turningSignal.1, step, R, C)
18             turningCount += 1
19             if (turningCount&1 == 0) {
20                 step += 1
21             }
22         }
23         
24         return ans
25     }
26     
27     private func move(_ direction: Bool, _ forward: Int, _ step: Int, _ R: Int, _ C: Int) {
28         for _ in 0..<step {
29             if direction {
30                 current[1] += forward
31             } else {
32                 current[0] += forward
33             }
34             let row = current[0]; let col = current[1]
35             if (row < R && row >= 0 && col < C && col >= 0) {
36                 ans.append(current)
37                 visited += 1
38             }
39         }
40     }
41 }

152ms

 1 class Solution {
 2     func spiralMatrixIII(_ R: Int, _ C: Int, _ r0: Int, _ c0: Int) -> [[Int]] {
 3         var count = 1
 4         var right = 0
 5         var down = 0
 6         var left = 0
 7         var up = 0
 8         var currentRow = r0
 9         var currentCol = c0
10         var pointsCount = 0
11         var visitedPoints:[[Int]] = []
12 
13         while pointsCount < R*C {
14             if currentRow >= 0 && currentRow < R && currentCol >= 0 && currentCol < C {
15                 pointsCount = pointsCount + 1
16                 visitedPoints.append([currentRow, currentCol])
17             }
18 
19             if right < count {
20                 currentCol  = currentCol + 1
21                 right = right + 1
22             }else if down < right {
23                 currentRow = currentRow + 1
24                 down = down + 1
25             }else if left < right + 1{
26                 currentCol  = currentCol - 1
27                 left = left + 1
28             }else if up < right + 1 {
29                 currentRow = currentRow - 1
30                 up = up + 1
31             }
32 
33             if up == right + 1 {
34                 count = count + 2
35                 right = 0
36                 down = 0
37                 left = 0
38                 up = 0
39             }
40         }
41         return visitedPoints
42     }
43 }

204ms

 1 class Solution {
 2     func spiralMatrixIII(_ R: Int, _ C: Int, _ r0: Int, _ c0: Int) -> [[Int]] {        
 3         var r = r0,c = c0,n = 1,direction = 1,count = 1
 4         var arr : Array<Array<Int>> = [[]]
 5         arr.removeAll()
 6         arr.append([r,c])
 7         while arr.count < R * C {
 8             
 9             switch direction%4 {//上右下左
10             case 0: r-=1
11             case 1: c+=1
12             case 2: r+=1
13             case 3: c-=1
14             default: break
15             }
16             if (r >= 0 && r < R && c >= 0 && c < C) {
17                 arr.append([r,c])
18             }
19             
20             if count < n {
21                 count += 1
22             } else {
23             if direction % 4 == 0 || direction % 4 == 2 {
24                 n+=1
25             }
26             count = 1
27        direction += 1
28             }
29         }
30         return arr        
31     }
32 }

212ms

 1 class Solution {
 2     func spiralMatrixIII(_ R: Int, _ C: Int, _ r0: Int, _ c0: Int) -> [[Int]] {
 3     var arr: [[Int]] = [[r0, c0]]
 4     
 5     // 0 →  1 ↓  2 ←  3 ↑
 6     var dir = 0
 7     var dis = 1, cis = 1
 8     var r = r0, c = c0
 9     let max = R * C
10     
11     while true {
12         if arr.count == max { break }
13         let n = next(dir, r, c)
14         r = n.0
15         c = n.1
16         
17         cis -= 1
18         if cis == 0 {
19             dir += 1
20             if dir % 2 == 0 {
21                 dis += 1
22             }
23             cis = dis
24         }
25         
26         if outRect(R, C, r, c: c) { continue }
27         arr.append([r, c])
28     }
29     
30     return arr
31 }
32 
33 func outRect(_ R: Int, _ C: Int, _ r: Int, c: Int) -> Bool {
34     return (r < 0 || r >= R) || (c < 0 || c >= C)
35 }
36 
37 func next(_ dir: Int, _ r: Int, _ c: Int) -> (Int, Int) {
38     let d = dir % 4
39     switch d {
40     case 0: return (r, c+1)
41     case 1: return (r+1, c)
42     case 2: return (r, c-1)
43     case 3: return (r-1, c)
44     default:return (r, c)
45     }
46   }
47 }

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