如果您使用的是UINavigationController，则可以使用popToRootViewController

import UIKit

class AViewController: UIViewController {}
class BViewController: UIViewController {}
class CViewController: UIViewController {}

let a = AViewController()
let b = BViewController()
let c = CViewController()

let nav = UINavigationController(rootViewController: a)
nav.pushViewController(b, animated: true)
nav.pushViewController(c, animated: true)

// Option 1
nav.popToRootViewController(animated: true)

// Option 2
nav.popToViewController(a, animated: true)

最简单的方法是使用UINavigationController：从A -〉B（A中的代码）：

navigationController?.pushViewController(ViewControllerB(), animated: true)

从B -〉C（这段代码在B中）：

navigationController?.pushViewController(ViewControllerC(), animated: true)

从C -〉A（C中的代码）：

navigatinoController?.popToRootViewController(animated: true)