[N-0] add 683

Author: fishercoder1534

README.md

@@ -48,6 +48,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |686|[Repeated String Match](https://leetcode.com/problems/repeated-string-match/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_686.java) | O(n*(m+n)) | O(m+n) | Easy | 
 |685|[Redundant Connection II](https://leetcode.com/problems/redundant-connection-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_685.java) | O(n) | O(n) | Hard | Union Find
 |684|[Redundant Connection](https://leetcode.com/problems/redundant-connection/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_684.java) | O(n) | O(n) | Medium | Union Find
+|683|[K Empty Slots](https://leetcode.com/problems/k-empty-slots/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_683.java) | O(n) | O(n) | Hard |
 |682|[Baseball Game](https://leetcode.com/problems/baseball-game/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_682.java) | O(n) | O(1) | Easy | 
 |681|[Next Closest Time](https://leetcode.com/problems/parents-closest-time/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_681.java) | O(1) | O(1) | Medium |
 |680|[Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_680.java) | O(n) | O(1) | Easy | String

src/main/java/com/fishercoder/solutions/_683.java

@@ -4,10 +4,15 @@
  * 683. K Empty Slots
  *
  *  There is a garden with N slots. In each slot, there is a flower.
+ *
  *  The N flowers will bloom one by one in N days.
+ *
  *  In each day, there will be exactly one flower blooming and it will be in the status of blooming since then.
+ *
  *  Given an array flowers consists of number from 1 to N. Each number in the array represents the place where the flower will open in that day.
- *  For example, flowers[i] = x means that the unique flower that blooms at day i will be at position x, where i and x will be in the range from 1 to N.
+ *  For example, flowers[i] = x means that the unique flower that blooms at day i will be at position x,
+ *  where i and x will be in the range from 1 to N.
+ *
  *  Also given an integer k, you need to output in which day there exists two flowers in the status of blooming,
  *  and also the number of flowers between them is k and these flowers are not blooming.
  *  If there isn't such day, output -1.
@@ -33,7 +38,23 @@ public class _683 {
 
     public static class Solution1 {
         public int kEmptySlots(int[] flowers, int k) {
-            return -1;
+            int[] days = new int[flowers.length];
+            for (int i = 0; i < flowers.length; i++) {
+                days[flowers[i] - 1] = i + 1;
+            }
+            int left = 0;
+            int right = k + 1;
+            int result = Integer.MAX_VALUE;
+            for (int i = 0; right < flowers.length; i++) {
+                if (days[i] < days[left] || days[i] <= days[right]) {
+                    if (i == right) {
+                        result = Math.min(result, Math.max(days[left], days[right]));
+                    }
+                    left = i;
+                    right = k + 1 + i;
+                }
+            }
+            return result == Integer.MAX_VALUE ? -1 : result;
         }
     }
 }

src/test/java/com/fishercoder/_683Test.java

@@ -0,0 +1,33 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._683;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _683Test {
+    private static _683.Solution1 solution1;
+    private static int[] flowers;
+    private static int k;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _683.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        flowers = new int[]{1, 3, 2};
+        k = 1;
+        assertEquals(2, solution1.kEmptySlots(flowers, k));
+    }
+
+    @Test
+    public void test2() {
+        flowers = new int[]{1, 2, 3};
+        k = 1;
+        assertEquals(-1, solution1.kEmptySlots(flowers, k));
+    }
+
+}