Swift 3-比较两个长度不等的数组，并在其中追加占位符的值，使它们相等

func makeArraysEqual(_ array1: inout [Int], _ array2: inout [Int], placeholder: Int) {
    let maxLength = max(array1.count, array2.count)
    
    while array1.count < maxLength {
        array1.append(placeholder)
    }
    
    while array2.count < maxLength {
        array2.append(placeholder)
    }
}

var array1 = [1, 2, 3]
var array2 = [4, 5, 6, 7, 8]

makeArraysEqual(&array1, &array2, placeholder: 0)

print(array1) // [1, 2, 3, 0, 0]
print(array2) // [4, 5, 6, 7, 8]