Problem_STOII_0005_maxProduct.cc

#include <iostream>
#include <string>
#include <unordered_map>
#include <vector>

using namespace std;

class Solution
{
 public:
  int maxProduct(vector<string> &words)
  {
    unordered_map<int, int> map;
    for (auto &word : words)
    {
      // 位运算优化
      int mask = 0;
      int n = word.length();
      for (auto &c : word)
      {
        mask |= (1 << (c - 'a'));
      }
      if (map.count(mask))
      {
        if (n > map[mask])
        {
          map[mask] = n;
        }
      }
      else
      {
        map[mask] = n;
      }
    }
    int ans = 0;
    for (auto &[mask1, len1] : map)
    {
      for (auto &[mask2, len2] : map)
      {
        if ((mask1 & mask2) == 0)
        {
          ans = std::max(ans, len1 * len2);
        }
      }
    }
    return ans;
  }
};