[N-0] add 693

Author: fishercoder1534

README.md

@@ -22,6 +22,7 @@ Your ideas/fixes/algorithms are more than welcome!
 
 |  #  |      Title     |   Solutions   | Time          | Space         | Difficulty  | Tag          | Notes
 |-----|----------------|---------------|---------------|---------------|-------------|--------------|-----
+|693|[Binary Number with Alternating Bits](https://leetcode.com/problems/binary-number-with-alternating-bits/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_693.java) | O(n) | O(1) | Easy | 
 |690|[Employee Importance](https://leetcode.com/problems/employee-importance/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_690.java) | O(n) | O(h) | Easy | DFS
 |688|[Knight Probability in Chessboard](https://leetcode.com/problems/knight-probability-in-chessboard/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_688.java) | O(n^2) | O(n^2) | Medium | DP
 |687|[Longest Univalue Path](https://leetcode.com/problems/longest-univalue-path/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_687.java) | O(n) | O(h) | Easy | DFS

src/main/java/com/fishercoder/solutions/_693.java

@@ -0,0 +1,43 @@
+package com.fishercoder.solutions;
+
+/**
+ * 693. Binary Number with Alternating Bits
+ *
+ * Given a positive integer, check whether it has alternating bits: namely, if two adjacent bits will always have different values.
+
+ Example 1:
+ Input: 5
+ Output: True
+ Explanation:
+ The binary representation of 5 is: 101
+
+ Example 2:
+ Input: 7
+ Output: False
+ Explanation:
+ The binary representation of 7 is: 111.
+
+ Example 3:
+ Input: 11
+ Output: False
+ Explanation:
+ The binary representation of 11 is: 1011.
+
+ Example 4:
+ Input: 10
+ Output: True
+ Explanation:
+ The binary representation of 10 is: 1010.
+ */
+
+public class _693 {
+    public boolean hasAlternatingBits(int n) {
+        String binaryStr = Integer.toBinaryString(n);
+        for (int i = 1; i < binaryStr.length(); i++) {
+            if (binaryStr.charAt(i - 1) == binaryStr.charAt(i)) {
+                return false;
+            }
+        }
+        return true;
+    }
+}