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Leetcode - 387. First Unique Character in a String

· One min read

https://leetcode.com/problems/first-unique-character-in-a-string/

Solution 1​

/**
 * @param {string} s
 * @return {number}
 */
var firstUniqChar = function (s) {
  const hashMap = {};
  for (let i = 0; i < s.length; i++) {
    if (hashMap[s[i]]) {
      hashMap[s[i]] = {
        ...hashMap[s[i]],
        count: hashMap[s[i]].count + 1,
      };
    } else {
      hashMap[s[i]] = {
        index: i,
        count: 1,
      };
    }
  }

  const filteredResult = Object.entries(hashMap)
    .map(([key, value]) => {
      if (value.count === 1) {
        return value.index;
      }
    })
    .filter((value) => value !== false && value !== undefined);

  return filteredResult.length === 0 ? -1 : filteredResult[0];
};