c# - 按顺序搜索缺失的数字

Question

假设我有以下数组(我的序列都是按升序排列的，并且包含正整数)

var tabSequence = new[] { 1, 2, 3, 7, 8, 9, 12, 15, 16, 17, 22, 23, 32 };

我使用 LINQ 和循环编写了一个代码来搜索丢失的数字:

List<Int32> lstSearch = new List<int>();
var lstGroup = tabSequence
    .Select((val, ind) => new { val, group = val - ind })
    .GroupBy(v => v.group, v => v.val)
    .Select(group => new{ GroupNumber = group.Key, Min = group.Min(), Max = group.Max() }).ToList();

for (int number = 0; number < lstGroup.Count; number++)
{
    if (number < lstGroup.Count-1)
    {
        for (int missingNumber = lstGroup[number].Max+1; missingNumber < lstGroup[number+1].Min; missingNumber++) 
            lstSearch.Add(missingNumber);
    }               
}       
var tabSequence2 = lstSearch.ToArray();
// Same result as var tabSequence2 = new[] {4, 5, 6, 10, 11, 13, 14, 18, 19, 20, 21, 24, 25, 26, 27, 28, 29, 30, 31 };

此代码有效，但我想知道是否有更好的方法仅使用 linq 来完成同样的事情。

Answer 1

也许我只是不明白这个问题。你的代码看起来很复杂，你可以让它变得更简单:

int[] tabSequence = new[] { 1, 2, 3, 7, 8, 9, 12, 15, 16, 17, 22, 23, 32 };

var results = Enumerable.Range(1, tabSequence.Max()).Except(tabSequence);

//results is: 4, 5, 6, 10, 11, 13, 14, 18, 19, 20, 21, 24, 25, 26, 27, 28, 29, 30, 31

我做了一个 fiddle here