LeetCode - Algorithms - 387. First Unique Character in a String

虽然是Easy的题，自己却想不出来，最后只好参考了这个 Given a string, find its first non-repeating character 的思路，倒也很容易看明白，一点就破的题。

Java

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
class Solution {
    public int firstUniqChar(String s) {
    	Map<Character,Integer> count = new HashMap<Character,Integer>();
    	char c = '\u0000';
    	for(int i=0;i<s.length();i++) {
    		c = s.charAt(i);
    		if (count.containsKey(c)) {
    			count.put(c, count.get(c)+1);
    		}
    		else {
    			count.put(c, 1);
    		}
    	}

        int r = -1;
        for(int i=0;i<s.length();i++) {
        	if (count.get(s.charAt(i))==1) {
        		r = i;
        		break;
        	}
        }
        return r;        
    }
}

Submission Detail

  • 104 / 104 test cases passed.
  • Runtime: 61 ms
  • Your runtime beats 25.39 % of java submissions.

JavaScript

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
/**
 * @param {string} s
 * @return {number}
 */
var firstUniqChar = function(s) {
	var count = {};
	for(var i=0;i<s.length;i++) {
		if (typeof count[s[i]]!="undefined" && count[s[i]]!=null) {
			count[s[i]]++;
		}
		else {
			count[s[i]]=1;
		}
	}
	var r=-1;
	for(var i=0;i<s.length;i++) {
		if (count[s[i]]==1) {
			r=i;
			break;
		}
	}
	return r;    
};

Submission Detail

  • 104 / 104 test cases passed.
  • Runtime: 108 ms
  • Your runtime beats 37.23 % of javascript submissions.