leetcode350

public class Solution
    {
        public int[] Intersect(int[] nums1, int[] nums2)
        {
            var len1 = nums1.Length;
            var len2 = nums2.Length;

            var list = new List<int>();//用于存放最后的结果

            var dic1 = new Dictionary<int, int>();//记录第一个数组的特征
            var dic2 = new Dictionary<int, int>();//记录第二个数组的特征

            for (int i = 0; i < len1; i++)
            {
                if (!dic1.ContainsKey(nums1[i]))
                {
                    dic1.Add(nums1[i], 1);
                }
                else
                {
                    dic1[nums1[i]]++;
                }
            }

            for (int i = 0; i < len2; i++)
            {
                if (!dic2.ContainsKey(nums2[i]))
                {
                    dic2.Add(nums2[i], 1);
                }
                else
                {
                    dic2[nums2[i]]++;
                }
            }

            if (dic1.Count <= dic2.Count)
            {
                //以dic1为基础循环

                foreach (var d in dic1)
                {
                    if (dic2.ContainsKey(d.Key))
                    {
                        var count = Math.Min(d.Value, dic2[d.Key]);
                        while (count > 0)
                        {
                            list.Add(d.Key);
                            count--;
                        }
                    }
                }
            }
            else
            {
                //以dic2为基础循环
                foreach (var d in dic2)
                {
                    if (dic1.ContainsKey(d.Key))
                    {
                        var count = Math.Min(d.Value, dic1[d.Key]);
                        while (count > 0)
                        {
                            list.Add(d.Key);
                            count--;
                        }
                    }
                }
            }

            foreach (var l in list)
            {
                Console.WriteLine(l);
            }

            return list.ToArray();
        }
    }

https://leetcode.com/problems/intersection-of-two-arrays-ii/#/description

 

补充一个python的实现：

class Solution:
    def intersect(self, nums1: 'List[int]', nums2: 'List[int]') -> 'List[int]':
        result = []
        c1 = collections.Counter(nums1)
        c2 = collections.Counter(nums2)
        for k in c1.keys():
            if k in c2:
                times = min(c1[k],c2[k])
                result += [k] * times
        return result