[Swift]LeetCode867. 转置矩阵 | Transpose Matrix

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Given a matrix A, return the transpose of A.

The transpose of a matrix is the matrix flipped over it's main diagonal, switching the row and column indices of the matrix. 

Example 1:

Input: [[1,2,3],[4,5,6],[7,8,9]]
Output: [[1,4,7],[2,5,8],[3,6,9]]

Example 2:

Input: [[1,2,3],[4,5,6]]
Output: [[1,4],[2,5],[3,6]] 

Note:

1. 1 <= A.length <= 1000
2. 1 <= A[0].length <= 1000

---

给定一个矩阵 A， 返回 A 的转置矩阵。

矩阵的转置是指将矩阵的主对角线翻转，交换矩阵的行索引与列索引。 

示例 1：

输入：[[1,2,3],[4,5,6],[7,8,9]]
输出：[[1,4,7],[2,5,8],[3,6,9]]

示例 2：

输入：[[1,2,3],[4,5,6]]
输出：[[1,4],[2,5],[3,6]] 

提示：

1. 1 <= A.length <= 1000
2. 1 <= A[0].length <= 1000

---

Runtime: 92 ms

Memory Usage: 19 MB

class Solution {
    func transpose(_ A: [[Int]]) -> [[Int]] {
        var tmp = Array(repeating: (Array(repeating:0, count: A.count)), count: A[0].count)
        for i in 0..<A[0].count {
            for j in 0..<A.count {
                tmp[i][j] = A[j][i]
            }
        }
        
        return tmp
    }
}

---

Runtime: 92 ms

Memory Usage: 19.2 MB

class Solution {
    func transpose(_ A: [[Int]]) -> [[Int]] {
        if A.count == 0 {
            return []
        }
        let count = A[0].count
        var R: [[Int]] = []
        for j in 0..<count {
          var r: [Int] = []
            for i in 0..<A.count {
                r.append(A[i][j])
            }
            R.append(r)
        }
        
        return R        
    }
}

---

116ms

class Solution {
func transpose(_ A: [[Int]]) -> [[Int]] {
    var result: [[Int]] = []
    for i in 0..<A[0].count {
        result.append([])
        for j in 0..<A.count {
            result[i].append(A[j][i])
        }
    }
    return result
  }
}

---

124ms

class Solution {
    func transpose(_ A: [[Int]]) -> [[Int]] {
        var x = A.count
        var y = A[0].count
        var result: [[Int]] = []
        
        for i in 0..<y {
            var list: [Int] = []
            for j in 0..<x {
                list += [A[j][i]]
            }
            result += [list]
        }
        
        return result        
    }
}

---

128ms

class Solution {
    func transpose(_ A: [[Int]]) -> [[Int]] {
        
        var row = -1
        var column = -1
        let result = Array(count: A[0].count) { () -> [Int] in
            row += 1
            column = -1
            return Array(count: A.count) { () -> Int in
                column += 1
                return A[column][row]
            }
        } 
        return result
    }
}

public extension Array {
    public init(count: Int, generator: @escaping() -> Element) {
        precondition(count >= 0, "arrays must have non-negative size")
        self.init((0..<count).lazy.map { Element in generator() })
    }
}