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➤微信公众号：山青咏芝（shanqingyongzhi）
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Given a positive integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.
Example:
Input: 3 Output: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ]
给定一个正整数 n，生成一个包含 1 到 n2 所有元素，且元素按顺时针顺序螺旋排列的正方形矩阵。
示例:
输入: 3 输出: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ]
8ms
1 class Solution { 2 func generateMatrix(_ n: Int) -> [[Int]] { 3 if n == 0 { 4 return [[Int]](); 5 } 6 var i = 0, j = 0; 7 var result = [[Int]]() 8 let m = n 9 var minI = -1, minJ = -1, maxI = m, maxJ = n; 10 11 let maxLength = m * n 12 13 var tempArray = [Int]() 14 for i in 0 ..< maxLength { 15 if tempArray.count == n { 16 result.append(tempArray) 17 tempArray.removeAll() 18 tempArray.append(i) 19 } else { 20 tempArray.append(i) 21 } 22 } 23 result.append(tempArray) 24 25 //action: 0: i+, 1: j+, 2: i-, 3: j- 26 var action = 1 27 var value = 1 28 29 30 while value <= maxLength { 31 switch action { 32 case 0: do { 33 while i < maxI { 34 result[i][j] = value 35 value += 1 36 i += 1 37 } 38 i -= 1 39 maxJ -= 1 40 41 action = 3 42 j -= 1 43 } 44 break; 45 case 1: do { 46 while j < maxJ { 47 result[i][j] = value 48 value += 1 49 j += 1 50 } 51 j -= 1 52 minI += 1 53 54 action = 0 55 i += 1 56 } 57 break; 58 case 2: do { 59 while i > minI { 60 result[i][j] = value 61 value += 1 62 i -= 1 63 } 64 i += 1 65 minJ += 1 66 67 action = 1 68 j += 1 69 } 70 break; 71 case 3: do { 72 while j > minJ { 73 result[i][j] = value 74 value += 1 75 j -= 1 76 } 77 j += 1 78 maxI -= 1 79 80 action = 2 81 i -= 1 82 } 83 break; 84 default: 85 break 86 } 87 } 88 return result; 89 } 90 }
12ms
1 class Solution { 2 func generateMatrix(_ n: Int) -> [[Int]] { 3 let iterations = n / 2 + n % 2 4 var arr = Array(repeating: (Array(repeating: 0, count: n)), count: n) 5 var value = 0 6 var count = n 7 var isIterating = false 8 for index in 0..<iterations { 9 var j = index 10 var i = index 11 12 13 14 while (j < count) { 15 value += 1 16 arr[i][j] = value 17 j += 1 18 isIterating = true 19 } 20 j -= 1 21 22 i += 1 23 while (i < count) { 24 value += 1 25 arr[i][j] = value 26 i += 1 27 isIterating = true 28 } 29 i -= 1 30 31 j -= 1 32 33 if !isIterating { break } 34 35 while(j >= index) { 36 value += 1 37 arr[i][j] = value 38 j -= 1 39 } 40 j += 1 41 42 i -= 1 43 44 while(i > index) { 45 value += 1 46 arr[i][j] = value 47 i -= 1 48 } 49 50 count -= 1 51 52 isIterating = false 53 } 54 55 return arr 56 } 57 }
12ms
1 class Solution { 2 func generateMatrix(_ n: Int) -> [[Int]] { 3 guard n > 0 else { 4 return [[Int]]() 5 } 6 7 var num = 1 8 var res = Array(repeating: Array(repeating: 0, count: n), count: n) 9 10 for layer in 0..<n / 2 { 11 let start = layer 12 let end = n - layer - 1 13 14 // top 15 for i in start..<end { 16 res[start][i] = num 17 num += 1 18 } 19 20 // right 21 for i in start..<end { 22 res[i][end] = num 23 num += 1 24 } 25 26 // bottom 27 for i in stride(from: end, to: start, by: -1) { 28 res[end][i] = num 29 num += 1 30 } 31 32 // left 33 for i in stride(from: end, to: start, by: -1) { 34 res[i][start] = num 35 num += 1 36 } 37 } 38 39 // handle the center one 40 if n % 2 != 0 { 41 res[n / 2][n / 2] = n * n 42 } 43 44 return res 45 } 46 }
16ms
1 class Solution { 2 func generateMatrix(_ n: Int) -> [[Int]] { 3 var n = n 4 var result = Array<[Int]>(repeating: Array<Int>(repeating: 0, count: n), count: n) 5 var i = 1 6 let max = n * n 7 var x = 0, y = 0 8 while i <= max { 9 while y < n && result[x][y] == 0 { //向右 10 result[x][y] = i 11 i += 1 12 y += 1 13 } 14 x += 1 15 y -= 1 16 while x < n && result[x][y] == 0 { //向下 17 result[x][y] = i 18 i += 1 19 x += 1 20 } 21 x -= 1 22 y -= 1 23 while y >= 0 && result[x][y] == 0 { //向左 24 result[x][y] = i 25 i += 1 26 y -= 1 27 } 28 y += 1 29 x -= 1 30 while x >= 0 && result[x][y] == 0 { //向上 31 result[x][y] = i 32 i += 1 33 x -= 1 34 } 35 x += 1 36 y += 1 37 n -= 1 38 } 39 return result 40 } 41 }
16ms
1 class Solution { 2 func generateMatrix(_ n: Int) -> [[Int]] { 3 4 var minRow = 0, maxRow = n - 1, minCol = 0, maxCol = n - 1 5 var result = [[Int]](repeating: [Int](repeating: 0, count: n), count: n) 6 7 var num = 0 8 while true { 9 for j in minCol...maxCol { 10 num += 1 11 result[minRow][j] = num 12 } 13 minRow += 1 14 if num == n * n { break } 15 16 for i in minRow...maxRow { 17 num += 1 18 result[i][maxCol] = num 19 } 20 maxCol -= 1 21 if num == n * n { break } 22 23 for j in (minCol...maxCol).reversed() { 24 num += 1 25 result[maxRow][j] = num 26 } 27 maxRow -= 1 28 if num == n * n { break } 29 30 for i in (minRow...maxRow).reversed() { 31 num += 1 32 result[i][minCol] = num 33 } 34 minCol += 1 35 if num == n * n { break } 36 } 37 38 return result 39 40 } 41 }
20ms
1 class Solution { 2 func generateMatrix(_ n: Int) -> [[Int]] { 3 var res = [[Int]](repeating: [Int](repeating: 0, count: n), count: n) 4 var k = 1 5 for i in 0..<(n/2){//圈数 6 for y in i..<(n-i){ 7 res[i][y] = k 8 k += 1 9 } 10 for x in (i+1)..<(n-1-i){ 11 res[x][n-1-i] = k 12 k += 1 13 } 14 for y in i..<(n-i){ 15 res[n-1-i][n-1-y] = k 16 k += 1 17 } 18 for x in (i+1)..<(n-1-i){ 19 res[n-1-x][i] = k 20 k += 1 21 } 22 } 23 if n % 2 != 0{ 24 res[n/2][n/2] = k 25 } 26 return res 27 } 28 }