566. 重塑矩阵

题目链接：https://leetcode-cn.com/problems/reshape-the-matrix/

执行用时：76 ms, 在所有 Swift 提交中击败了100.00%的用户
内存消耗：13.6 MB, 在所有 Swift 提交中击败了97.37%的用户

1.每次内循环判断新的矩阵宽度是否符合要求

class Solution {
    func matrixReshape(_ mat: [[Int]], _ r: Int, _ c: Int) -> [[Int]] {
        let m = mat.count, n = mat[0].count
        if m*n != r*c {
            return mat
        }
        var res : [[Int]] = []
        var current : [Int] = []
        for i in 0 ..< m {
            for j in 0 ..< n {
                current.append(mat[i][j])
                if current.count == c {
                    res.append(current)
                    current = []
                }
            }
        }
        return res
    }
}

2.取出全部再放回

class Solution {
    func matrixReshape(_ mat: [[Int]], _ r: Int, _ c: Int) -> [[Int]] {
        var res = [[Int]].init(repeating: [], count: r)
        let m = mat.count, n = mat[0].count
        if m*n != r*c {
            return mat
        }
        var warehouse = [Int]()
        for i in 0 ..< m {
            for j in 0 ..< n {
                warehouse.append(mat[i][j])
            }
        }
        var index = 0;
        for i in 0 ..< r {
            for j in 0 ..< c {
                res[i].append(warehouse[index])
                index += 1
            }
        }
        return res
    }
}