changes

Author: Rakesh Venkatesh

src/leetcode/LC125.java

@@ -0,0 +1,27 @@
+package leetcode;
+
+public class LC125 {
+    public boolean isPalindrome(String s) {
+        int start = 0;
+        int last = s.length() - 1;
+
+        while (start <= last) {
+            char currFirst = s.charAt(start);
+            char currLast = s.charAt(last);
+
+            if (!Character.isLetterOrDigit(currFirst)) {
+                start++;
+            } else if (!Character.isLetterOrDigit(currLast)) {
+                last--;
+            } else {
+                if (Character.toLowerCase(currFirst) != Character.toLowerCase(currLast)) {
+                    return false;
+                }
+                start++;
+                last--;
+            }
+        }
+
+        return true;
+    }
+}

src/leetcode/LC680.java

@@ -0,0 +1,41 @@
+package leetcode;
+
+public class LC680 {
+
+    public boolean validPalindrome(String s) {
+        // base case
+        if (s == null || s.isEmpty()) {
+            return false;
+        }
+
+        for (int i = 0, j = s.length() -1; i < j; i++, j--) {
+            if (s.charAt(i) != s.charAt(j)) {
+                int i1 = i + 1, j1 = j, i2 = i, j2 = j - 1;
+
+                while (i1 < j1 && s.charAt(i1) == s.charAt(j1)) {
+                    i1++;
+                    j1--;
+                }
+                if (i1 >= j1) {
+                    return true;
+                }
+
+                while (i2 < j2 && s.charAt(i2) == s.charAt(j2)) {
+                    i2++;
+                    j2--;
+                }
+
+                return i2 >= j2;
+            }
+        }
+
+        return true;
+    }
+
+    public static void main(String[] args) {
+        LC680 lc680 = new LC680();
+        System.out.println(lc680.validPalindrome("aba"));  // Output: true
+        System.out.println(lc680.validPalindrome("abca"));  // Output: true
+        System.out.println(lc680.validPalindrome("abc"));  // Output: false
+    }
+}