First Unique Character in a String
Given a string, find the first non-repeating character in it and return it's index. If it doesn't exist, return -1.
Examples:
s = "leetcode"
return 0.
s = "loveleetcode",
return 2.
Note: You may assume the string contain only lowercase English letters.
class Solution {
public int firstUniqChar(String s) {
HashMap<Character, Integer> map = new HashMap<>();
for (char c : s.toCharArray())
map.put(c, map.getOrDefault(c, 0) + 1);
int ans = -1;
for (int i = 0; i < s.length(); i++) {
if (map.get(s.charAt(i)) == 1) {
ans = i;
break;
}
}
return ans;
}
}
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