LeetCode 347. Top K Frequent Elements(出现频率最多的 k 个元素)

class Solution {
public:
    vector<int> v[100010];
    vector<int> topKFrequent(vector<int>& nums, int k) {
        int len = nums.size();
        map<int, int> mp;
        for(int i = 0; i < len; ++i){
            ++mp[nums[i]];
        }
        int ma = 0;
        for(map<int, int>::iterator it = mp.begin(); it != mp.end(); ++it){
            v[it -> second].push_back(it -> first);
            ma = max(ma, it -> second);
        }
        int sum = 0;
        vector<int> ans;
        for(int i = ma; i >= 1; --i){
            len = v[i].size();
            if(sum + len <= k){
                sum += len;
                for(int j = 0; j < len; ++j){
                    ans.push_back(v[i][j]);
                }
            }
            else{
                for(int j = 0; j < len && j < k - sum; ++j){
                    ans.push_back(v[i][j]);
                }
                break;
            }
        }
        return ans;
    }
};