697. Degree of an Array

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problem

solution

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class Solution {
public:
    int findShortestSubArray(vector<int>& nums) {
        unordered_map<int,vector<int>> mp;
        int n = nums.size();
        for(int i=0;i<n;++i){
            mp[nums[i]].push_back(i);
        }
        
        int degree = 0;
        for(auto it=mp.begin();it!=mp.end();it++) degree=max(degree,int(it->second.size()));
        int shortest=nums.size();
        for(auto it=mp.begin();it!=mp.end();it++)
        {
           if(it->second.size()==degree)
            {
                shortest=min(shortest,it->second.back()-it->second[0]+1);
            } 
        }
        return shortest;
    }
};

analysis

  • time complexity O(n)
  • space complexity O(n)