1657.cpp

#include <map>
#include <set>
#include <string>
#include <vector>
using namespace std;

class Solution {
 public:
  bool closeStrings(string word1, string word2) {
    map<char, int> m1, m2;
    set<char> s1, s2;
    vector<int> occ1, occ2;
    for (const char c : word1) {
      ++m1[c];
      s1.insert(c);
    }

    for (const char c : word2) {
      ++m2[c];
      s2.insert(c);
    }
    if (s1 != s2)  // check if they use the same alphabet set.
      return false;
    for (const auto elem : m1) occ1.push_back(elem.second);
    for (const auto elem : m2) occ2.push_back(elem.second);
    sort(occ1.begin(), occ1.end());
    sort(occ2.begin(), occ2.end());
    for (int i = 0; i < occ1.size(); i++)  // check occurence
      if (occ1[i] != occ2[i]) return false;
    return true;
  }
};