[map] value sort ( C++ )

 

1. map → set 

#include <iostream>
#include <set>
#include <map>
 
using namespace std;
 
struct setCompare {
    bool operator()(const pair<int, int> &lhs, const pair<int, int> &rhs) {
        if (lhs.second == rhs.second) return lhs.first < rhs.first;
        return lhs.second < rhs.second;
    }
};
 
int main() {
    map<int, int> m;
    set<pair<int, int>, setCompare> s;
    for (auto it = m.begin(); it != m.end(); it++) {
        s.insert(*it);
    return 0;
}

---

2. map → vector

#include <iostream>
#include <algorithm>
#include <map>
#include <vector>
 
using namespace std;
 
bool cmp(pair<int, int> left , pair<int, int> right ) {
    return left.second < right.second;
}
int main() {
    map<int, int> m;
    vector <pair<int, int>> v;
    
    // key-value 값 복사
    copy(m.begin(), m.end(), back_inserter<vector<pair<int, int>>>(v));
 
    // value 기준 정렬
    sort(v.begin(), v.end(), cmp);
    return 0;
}