solve 387.first-unique-character-in-a-string

Author: andavid

vscode/387.first-unique-character-in-a-string.java

@@ -0,0 +1,47 @@
+/*
+ * @lc app=leetcode id=387 lang=java
+ *
+ * [387] First Unique Character in a String
+ *
+ * https://leetcode.com/problems/first-unique-character-in-a-string/description/
+ *
+ * algorithms
+ * Easy (49.20%)
+ * Total Accepted:    253.6K
+ * Total Submissions: 510.2K
+ * Testcase Example:  '"leetcode"'
+ *
+ *
+ * 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 letters.
+ *
+ */
+class Solution {
+  public int firstUniqChar(String s) {
+    int len = s.length();
+    int[] count = new int[26];
+    for (int i = 0; i < len; i++) {
+      count[s.charAt(i) - 'a']++;
+    }
+    for (int i = 0; i < len; i++) {
+      if (count[s.charAt(i) - 'a'] == 1) {
+        return i;
+      }
+    }
+    return -1;
+  }
+}
+