Minimum Operations to Make a Uni-Value Grid.cpp

class Solution {
public:
    int minOperations(vector<vector<int>>& grid, int x) {
        vector<int>nums;
        int m=grid.size(),n=grid[0].size();
        for(int i=0;i<m;i++)
            for(int j=0;j<n;j++)
                nums.push_back(grid[i][j]);
        sort(nums.begin(),nums.end());
        int target=nums[m*n/2],ans=0;
        for(int i=m*n-1;i>=0;i--){
            if(abs(nums[i]-target)%x!=0)
                return -1;
            else
                ans+=abs(nums[i]-target)/x;  
        }
        return ans;
    }
};