leetcode 697.Degree of an Array

class Solution {
public:
    int findShortestSubArray(vector<int>& nums) {
        map<int,int> m;
        map<int,pair<int,int>> pos;
        int degree=0,res=INT_MAX;
        for(int i=0;i<nums.size();i++){
            m[nums[i]]++;
            if(m[nums[i]]==1){
                pos[nums[i]]={i,i};
            }else{
                pos[nums[i]].second=i;
            }
            degree=max(degree, m[nums[i]]);
        }
        for(auto a:m){
            if(degree==a.second){
                res=min(res,pos[a.first].second-pos[a.first].first+1);
            }
        }
        return res;
    }
};