21 June | 2448. Minimum Cost to Make Array Equal.cpp

class Solution {
public:

    long long helper(vector<int>& nums, vector<int>& cost, int all){
        long long totalCost = 0LL;
        for(int i = 0; i < nums.size(); i++){
            totalCost += 1LL * abs(nums[i] - all) * cost[i];
        }
        return totalCost;
    }
    
    long long minCost(vector<int>& nums, vector<int>& cost) {
        int left = nums[0];
        int right = nums[0];

        for(int i : nums){
            left = min(left, i);
            right = max(right, i);
        }
        long long ans = 0;
        while(left< right){
            int mid = (left+right)/2;
            long long cost1 = helper(nums, cost, mid);
            long long cost2 = helper(nums, cost, mid+1);
            if(cost1 > cost2){
                left = mid+1;
                ans = cost2;
            }
            else{
                right = mid;
                ans = cost1;
            }
        }
        return ans;
    }
};