Weight for weight

• Time : $O(|s| + nlogn)$
• Space : $O(n)$

#include <bits/stdc++.h>
using namespace std;
class WeightSort
{
public:
    static std::string orderWeight(const std::string &strng) {
        unordered_map<string, long long> weight;
        vector<string> S;
        string now = "";
        long long cost = 0;
        for(auto ch : strng) {
            if(ch == ' ') {
                if(now.length()) {
                    weight[now] = cost;
                    S.push_back(now);
                    now = "", cost = 0;
                }
            } else now.push_back(ch), cost += ch - '0';
        }
        if(now.length()) {
            weight[now] = cost;
            S.push_back(now);
            now = "", cost = 0;
        }

        sort(begin(S), end(S), [&](auto& a, auto& b) {
            if(weight[a] != weight[b]) return weight[a] < weight[b];
            return a < b;
        });
        string res = "";
        for(auto s : S) res += s + " ";
        while(res.length() and res.back() == ' ') res.pop_back();
        return res;
    }
};