检测两个字符串是否有共同的字符

正则

// ["a","ab","abc","d","cd","bcd","abcd"] 两个串没有重叠部分，最长乘积
var maxProduct = function (words) {
    
    
  var max = 0
  for (var i = 0; i < words.length; i++) {
    
    
    for (var j = i + 1; j < words.length; j++) {
    
    
      var value = f(words[i], words[j])
      max = Math.max(max, value)
    }
  }
  return max
  function f(s1, s2) {
    
    
    var set = Array.from([...s2]).join('')
    var reg = new RegExp(`[${
      
      set}]`)
    var flag = reg.test(s1)
    if (flag) return 0
    return s1.length * s2.length
  }
}

使用charCode

function f(s1, s2) {
    
    
  var str1
  for (var i = 0; i < s1.length; i++) {
    
    
    str1 |= 1 << (s1[i].charCodeAt() - 'a'.charCodeAt())
  }
  var str2
  for (var i = 0; i < s2.length; i++) {
    
    
    str2 |= 1 << (s2[i].charCodeAt() - 'a'.charCodeAt())
  }
  return !!(str1 & str2)
}