https://leetcode-cn.com/problems/is-unique-lcci/
image.png

解法1

  1. /**
  2.  * @param {string} astr
  3.  * @return {boolean}
  4.  */
  5. var isUnique = function(astr) {
  6.     let arr = astr.split('');
  7.     let narr = [];
  8.     arr.forEach(it=>{
  9.         if(!(narr.includes(it))){
  10.             narr.push(it)
  11.         }
  12.         return narr;
  13.     })
  14.     return arr.length === narr.length
  15. };

解法2 (ES6)

  1. /**
  2.  * @param {string} astr
  3.  * @return {boolean}
  4.  */
  5. var isUnique = function(astr) {
  6.     return astr.length == new Set(astr).size;
  7. };