swift操场错误错误错误指示

因此，我有以下贪婪算法，它给出了以下错误：

执行中止：错误：执行被中断， 原因：EXC_错误指令（代码=EXC_I386_INVOP，子代码=0x0）。这个 进程被留在中断的位置，请使用 “thread return-x”返回到表达式之前的状态 评估

类别：

// This class represents an undirected graph using adjacency list
public class Graph{
    var V: Int // number of vertices
    var adj: [[Int]] = [[]] //Adjacency List

    public init(v: Int) {
        V = v
        adj = [[Int]](repeating: [], count: v)
    }

    // Function to add an edge into the graph
    public func addEdge(v: Int, w: Int){
        adj[v].append(w)
        adj[w].append(v) // Graph is undirected
    }

    // Assigns colors (starting from 0) to all vertices and
    // prints the assignment of colors
    public func greedyColoring() {
        var result = [Int]()

        //Assign the first color to first vertex
        result[0] = 0

        //Initialize the remaining V-1 vertices as unassigned
        for i in 0 ..< V{
            //No Color is assigned
            result[i] = -1
        }

        // A temporary array to store the available colors. True
        // value of available[cr] would mean that the color cr is
        // assigned to one of its adjacent vertices
        var available = [Bool]()
        for cr in 0 ..< V{
            available[cr] = false
        }

        // Assign colors to remaining V-1 vertices
        for i in 1 ..< V{
            //Process all adjacent vertices and flag their colors as unavailable
            for un in 0 ..< adj[i].count{
                if result[un] != -1 {
                    available[result[un]] = true
                }
            }

            //find the first available color
            for cr in 0 ..< V{
                if available[cr] == false{
                    result[i] = cr
                    break
                }
            }

            //Reset the values back to false for the next iteraation
            for un in 0 ..< adj[i].count{
                if result[un] != -1 {
                    available[result[un]] = true
                }
            }
        }

        //Print result
        for r in 0 ..< V{
            print("Vertex \(r) --> Color \(result[r])")
        }
    }
}

import Foundation
import UIKit
import XCPlayground

var g1 = Graph(v: 5)
g1.addEdge(v: 0, w: 1)
g1.addEdge(v: 0, w: 2)
g1.addEdge(v: 1, w: 2)
g1.addEdge(v: 1, w: 3)
g1.addEdge(v: 2, w: 3)
g1.addEdge(v: 3, w: 4)
g1.greedyColoring() // Fails HERE

所以我在前面的一些行中出现了这个错误，它与我如何使用数组有关。为什么游乐场不给出一个确切的错误，比如

索引超出界限之类的？

我的调试控制台不打印任何内容。。。我的代码中出现错误的原因是什么

在此代码片段中：

var result = [Int]()

//Assign the first color to first vertex
result[0] = 0

数组

result

为空，因此无法通过

result[0]

访问第一个元素

解决方案：

// This class represents an undirected graph using adjacency list
public class Graph{
    var V: Int // number of vertices
    var adj: [[Int]] = [[]] //Adjacency List

    public init(v: Int) {
        V = v
        adj = [[Int]](repeating: [], count: v)
    }

    // Function to add an edge into the graph
    public func addEdge(v: Int, w: Int){
        adj[v].append(w)
        adj[w].append(v) // Graph is undirected
    }

    // Assigns colors (starting from 0) to all vertices and
    // prints the assignment of colors
    public func greedyColoring() {
        var result = [Int]()

        //Assign the first color to first vertex
        result[0] = 0

        //Initialize the remaining V-1 vertices as unassigned
        for i in 0 ..< V{
            //No Color is assigned
            result[i] = -1
        }

        // A temporary array to store the available colors. True
        // value of available[cr] would mean that the color cr is
        // assigned to one of its adjacent vertices
        var available = [Bool]()
        for cr in 0 ..< V{
            available[cr] = false
        }

        // Assign colors to remaining V-1 vertices
        for i in 1 ..< V{
            //Process all adjacent vertices and flag their colors as unavailable
            for un in 0 ..< adj[i].count{
                if result[un] != -1 {
                    available[result[un]] = true
                }
            }

            //find the first available color
            for cr in 0 ..< V{
                if available[cr] == false{
                    result[i] = cr
                    break
                }
            }

            //Reset the values back to false for the next iteraation
            for un in 0 ..< adj[i].count{
                if result[un] != -1 {
                    available[result[un]] = true
                }
            }
        }

        //Print result
        for r in 0 ..< V{
            print("Vertex \(r) --> Color \(result[r])")
        }
    }
}

import Foundation
import UIKit
import XCPlayground

var g1 = Graph(v: 5)
g1.addEdge(v: 0, w: 1)
g1.addEdge(v: 0, w: 2)
g1.addEdge(v: 1, w: 2)
g1.addEdge(v: 1, w: 3)
g1.addEdge(v: 2, w: 3)
g1.addEdge(v: 3, w: 4)
g1.greedyColoring() // Fails HERE

更改为：

var result = [Int]()

//Assign the first color to first vertex
result[0] = 0

//Initialize the remaining V-1 vertices as unassigned
for i in 0 ..< V{
    //No Color is assigned
    result[i] = -1
}

// A temporary array to store the available colors. True
// value of available[cr] would mean that the color cr is
// assigned to one of its adjacent vertices
var available = [Bool]()
for cr in 0 ..< V{
    available[cr] = false
}

var结果=[Int]（）
//将第一种颜色指定给第一个顶点
结果[0]=0
//将其余V-1顶点初始化为未指定顶点
对于0..

致：

var结果=[Int]（）
//将第一种颜色指定给第一个顶点
结果。追加（0）
//将其余V-1顶点初始化为未指定顶点
对于0..

只要写下：

import PlaygroundSupport

---

这对我很有帮助

完美，有没有办法更好地调试操场？我的日志会打印出

致命错误：索引超出范围

，你呢？我的xcode只显示我发布的错误，而不显示在日志中。你打开调试控制台了吗？试着按一下⇧ + ⌘ + 如果我将图形代码从单独的类切换到主类，调试控制台会显示错误（索引超出范围）在Xcode-12.5上不起作用