贪心地想：要尽可能地减少连续相同字符，所以我们需要尽可能地将字符均匀排列
code

#include <iostream>
#include <vector>
#include <algorithm>
#include <unordered_map>

using namespace std;

string reorderString(int n, string s) {
    unordered_map<char, int> freq;
    for (char c : s) {
        freq[c]++;
    }
    
    vector<pair<char, int>> charFreqPairs;
    for (auto& p : freq) {
        charFreqPairs.push_back(p);
    }
    
    // 按照频率从高到低排序
    sort(charFreqPairs.begin(), charFreqPairs.end(), [](const pair<char, int>& a, const pair<char, int>& b) {
        return a.second > b.second;
    });
    
    string result;
    result.reserve(n);
    
    // 尝试均匀分布字符
    while (!charFreqPairs.empty()) {
        auto& top = charFreqPairs[0];
        result.push_back(top.first);
        top.second--;
        
        if (top.second == 0) {
            charFreqPairs.erase(charFreqPairs.begin());
        }
        
        if (charFreqPairs.size() > 1) {
            auto& second = charFreqPairs[1];
            result.push_back(second.first);
            second.second--;
            
            if (second.second == 0) {
                charFreqPairs.erase(charFreqPairs.begin() + 1);
            }
        }
    }
    
    return result;
}

int main() {
    int t;
    cin >> t;
    while (t--) {
        int n;
        string s;
        cin >> n >> s;
        cout << reorderString(n, s) << endl;
    }
    return 0;
}
JIUZHE

C. Turtle and Good Pairs

code
