718. Maximum Length of Repeated Subarray

FindLength.cs

public class Solution {
  public int FindLength(int[] nums1, int[] nums2) {
    if(nums2.Length > nums1.Length)
      (nums1, nums2) = (nums2, nums1);
    
    var root = CreateTrie(nums1);
    var maxLength = 0;
    
    for(var i = 0; i < nums2.Length; ++i){
      var current = root;
      var subArrayLength = 0;
      for(var j = i; j < nums2.Length; ++j){
        var num = nums2[j];
        if(!current.Children.ContainsKey(num)){
          break;
        }
        current = current.Children[num];
        subArrayLength++;
      }
      maxLength = Math.Max(maxLength, subArrayLength);
    }
    
    return maxLength;
  }
  
  private static Trie CreateTrie(int[] array){
    var root = new Trie(new());
    for(var i = 0; i < array.Length; ++i){
      var current = root;
      for(var j = i; j < array.Length; ++j){
        var num = array[j];
        if(current.Children.ContainsKey(num)){
          current = current.Children[num];
          continue;
        }
        var trie =  new Trie(new());
        current = current.Children[num] = trie;
      }
    }
    return root;
  }
  
  record struct Trie(Dictionary<int, Trie> Children);
}