add 1009

fishercoder1534 · fishercoder1534 · commit 22f3385318f2 · 2019-04-13T18:05:32.000-07:00
diff --git a/README.md b/README.md
@@ -31,6 +31,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |1021|[Remove Outermost Parentheses](https://leetcode.com/problems/remove-outermost-parentheses/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1021.java) | O(n) | O(n) | |Easy|
 |1018|[Binary Prefix Divisible By 5](https://leetcode.com/problems/binary-prefix-divisible-by-5/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1018.java) | O(n) | O(1) | |Easy|
 |1013|[Pairs of Songs With Total Durations Divisible by 60](https://leetcode.com/problems/pairs-of-songs-with-total-durations-divisible-by-60/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1013.java) | O(n) | O(1) | |Easy|
+|1009|[Complement of Base 10 Integer](https://leetcode.com/problems/complement-of-base-10-integer/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1009.java) | O(n) | O(1) | |Easy|
 |1002|[Find Common Characters](https://leetcode.com/problems/find-common-characters/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1002.java) | O(n) | O(1) | |Easy|
 |999|[Available Captures for Rook](https://leetcode.com/problems/available-captures-for-rook/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_999.java) | O(1) | O(1) | |Easy|
 |997|[Find the Town Judge](https://leetcode.com/problems/find-the-town-judge/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_997.java) | O(n) | O(n) | |Easy| 
diff --git a/src/main/java/com/fishercoder/solutions/_1009.java b/src/main/java/com/fishercoder/solutions/_1009.java
@@ -0,0 +1,60 @@
+package com.fishercoder.solutions;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * 1009. Complement of Base 10 Integer
+ *
+ * Every non-negative integer N has a binary representation.
+ * For example, 5 can be represented as "101" in binary,
+ * 11 as "1011" in binary, and so on.
+ *
+ * Note that except for N = 0, there are no leading zeroes in any binary representation.
+ *
+ * The complement of a binary representation is the number in binary you get when
+ * changing every 1 to a 0 and 0 to a 1.  For example, the complement of "101" in binary is "010" in binary.
+ *
+ * For a given number N in base-10, return the complement of it's binary representation as a base-10 integer.
+ *
+ * Example 1:
+ * Input: 5
+ * Output: 2
+ * Explanation: 5 is "101" in binary, with complement "010" in binary, which is 2 in base-10.
+ *
+ * Example 2:
+ * Input: 7
+ * Output: 0
+ * Explanation: 7 is "111" in binary, with complement "000" in binary, which is 0 in base-10.
+ *
+ * Example 3:
+ * Input: 10
+ * Output: 5
+ * Explanation: 10 is "1010" in binary, with complement "0101" in binary, which is 5 in base-10.
+ *
+ * Note:
+ * 0 <= N < 10^9
+ * */
+public class _1009 {
+    public static class Solution1 {
+        public int bitwiseComplement(int N) {
+            if (N == 0) {
+                return 1;
+            }
+            List<Integer> list = new ArrayList<>();
+            while (N != 0) {
+                list.add(N & 1);
+                N >>= 1;
+            }
+            int result = 0;
+            int exp = list.size() - 1;
+            for (int i = list.size() - 1; i >= 0; i--) {
+                if (list.get(i) == 0) {
+                    result += Math.pow(2, exp);
+                }
+                exp--;
+            }
+            return result;
+        }
+    }
+}
diff --git a/src/test/java/com/fishercoder/_1009Test.java b/src/test/java/com/fishercoder/_1009Test.java
@@ -0,0 +1,42 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1009;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1009Test {
+    private static _1009.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1009.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(2, solution1.bitwiseComplement(5));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals(5, solution1.bitwiseComplement(10));
+    }
+
+    @Test
+    public void test3() {
+        assertEquals(0, solution1.bitwiseComplement(7));
+    }
+
+    @Test
+    public void test4() {
+        assertEquals(3, solution1.bitwiseComplement(12));
+    }
+
+    @Test
+    public void test5() {
+        assertEquals(1, solution1.bitwiseComplement(0));
+    }
+
+}
