modify code

Author: algorithmzuo

src/topinterviewquestions/Problem_0387_FirstUniqueCharacterInString.java

@@ -9,7 +9,7 @@ public int firstUniqChar(String s) {
 		for (int i = 0; i < N; i++) {
 			count[str[i] - 'a']++;
 		}
-		for (int i = 0; i < s.length(); i++) {
+		for (int i = 0; i < N; i++) {
 			if (count[str[i] - 'a'] == 1) {
 				return i;
 			}