Fixed idea warnings.

Author: javadev

src/main/java/g0101_0200/s0125_valid_palindrome/Solution.java

@@ -9,11 +9,11 @@ public boolean isPalindrome(String s) {
             // Iterates through string to find first char which is alphanumeric.
             // Done to ignore non-alphanumeric characters.
             // Starts from 0 to j-1.
-            while (i < j && !isAlphaNumeric(s.charAt(i))) {
+            while (i < j && isNotAlphaNumeric(s.charAt(i))) {
                 i++;
             }
             // Similarly from j-1 to 0.
-            while (i < j && !isAlphaNumeric(s.charAt(j))) {
+            while (i < j && isNotAlphaNumeric(s.charAt(j))) {
                 j--;
             }
             // Checks if i is greater than or equal to j.
@@ -39,8 +39,8 @@ public boolean isPalindrome(String s) {
         return res;
     }
 
-    private boolean isAlphaNumeric(char c) {
-        return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9');
+    private boolean isNotAlphaNumeric(char c) {
+        return (c < 'a' || c > 'z') && (c < 'A' || c > 'Z') && (c < '0' || c > '9');
     }
 
     private boolean isUpper(char c) {

src/main/java/g0201_0300/s0211_design_add_and_search_words_data_structure/WordDictionary.java

@@ -31,9 +31,7 @@ public boolean search(String word) {
         for (String s : a) {
             boolean match = true;
             for (int i = 0; i < word.length() && match; i++) {
-                if (word.charAt(i) == '.') {
-                    continue;
-                } else if (s.charAt(i) != word.charAt(i)) {
+                if (word.charAt(i) != '.' && s.charAt(i) != word.charAt(i)) {
                     match = false;
                 }
             }

src/main/java/g0201_0300/s0218_the_skyline_problem/Solution.java

@@ -2,7 +2,6 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.TreeMap;
 
@@ -14,7 +13,7 @@ public List<List<Integer>> getSkyline(int[][] buildings) {
             lines.add(new int[] {building[0], building[2]});
             lines.add(new int[] {building[1], -building[2]});
         }
-        Collections.sort(lines, (a, b) -> a[0] == b[0] ? b[1] - a[1] : a[0] - b[0]);
+        lines.sort((a, b) -> a[0] == b[0] ? b[1] - a[1] : a[0] - b[0]);
         TreeMap<Integer, Integer> map = new TreeMap<>();
         map.put(0, 1);
         int prev = 0;

src/main/java/g0201_0300/s0236_lowest_common_ancestor_of_a_binary_tree/Solution.java

@@ -27,9 +27,6 @@ public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
         if (left != null) {
             return left;
         }
-        if (right != null) {
-            return right;
-        }
-        return null;
+        return right;
     }
 }