761. 特殊的二进制序列(分治)

可等价为括号序列。

class Solution {
public:
    string makeLargestSpecial(string s) {
        if (s.size() <= 2) {
            return s;
        }
        int cnt = 0, left = 0;
        vector<string> subs;
        for (int i = 0; i < s.size(); ++i) {
            if (s[i] == '1') {
                ++cnt;
            }
            else {
                --cnt;
                if (cnt == 0) {
                    subs.push_back("1" + makeLargestSpecial(s.substr(left + 1, i - left - 1)) + "0");
                    left = i + 1;
                }
            }
        }

        sort(subs.begin(), subs.end(), greater<string>{});
        string ans = accumulate(subs.begin(), subs.end(), ""s);
        return ans;
    }
};