lc t3

class Solution {
    using ll = long long;
    using pii = pair<int, int>;
public:
    long long minCost(vector<int>& nums, vector<int>& cost) {
        vector<pii> v(nums.size());
        ll total = 0;
        for (int i = 0; i < v.size(); ++i) v[i] = {nums[i], cost[i]}, total += cost[i];
        sort(v.begin(), v.end());
        ll ret = 0;
        int lb = 0, ub = v.size() - 1;
        while (lb < ub) {
            ll c = min(v[lb].second, v[ub].second);
            ret += c * (v[ub].first - v[lb].first);
            v[lb].second -= c;
            v[ub].second -= c;
            if (v[lb].second == 0) ++lb;
            if (v[ub].second == 0) --ub;
        }

        return ret;
    }
};