Add some code

leetcode/problems/java/reverse-string.java

@@ -0,0 +1,10 @@
+class Solution {
+  public void reverseString(char[] s) {
+    int n = s.length;
+    for (int i = 0; i < n / 2; i++) {
+      char temp = s[i];
+      s[i] = s[n - i - 1];
+      s[n - i - 1] = temp;
+    }
+  }
+}

leetcode/problems/java/score-of-a-string.java

@@ -0,0 +1,11 @@
+class Solution {
+  public int scoreOfString(String s) {
+    int score = 0;
+    int n = s.length();
+    for (int i = 0; i < n - 1; i++) {
+      int diff = Math.abs(s.charAt(i + 1) - s.charAt(i));
+      score += diff;
+    }
+    return score;
+  }
+}