add 849

Author: fishercoder1534

README.md

@@ -86,6 +86,7 @@ Your ideas/fixes/algorithms are more than welcome!
 |860|[Lemonade Change](https://leetcode.com/problems/lemonade-change/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_860.java) | O(n) | O(1) | |Easy|
 |859|[Buddy Strings](https://leetcode.com/problems/buddy-strings/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_859.java) | O(n) | O(n) | |Easy|
 |852|[Peak Index in a Mountain Array](https://leetcode.com/problems/peak-index-in-a-mountain-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_852.java) | O(n) | O(1) | |Easy|
+|849|[Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_849.java) | O(n^2) | O(1) | |Easy|
 |844|[Backspace String Compare](https://leetcode.com/problems/backspace-string-compare/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_844.java) | O(n) | O(1) | |Easy|
 |840|[Magic Squares In Grid](https://leetcode.com/problems/magic-squares-in-grid/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_840.java) | O(1) | O(1) | |Easy|
 |832|[Flipping an Image](https://leetcode.com/problems/flipping-an-image/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_832.java) | O(n) | O(1) | |Easy|

src/main/java/com/fishercoder/solutions/_849.java

@@ -0,0 +1,74 @@
+package com.fishercoder.solutions;
+
+/**
+ * 849. Maximize Distance to Closest Person
+ *
+ * In a row of seats, 1 represents a person sitting in that seat, and 0 represents that the seat is empty.
+ * There is at least one empty seat, and at least one person sitting.
+ * Alex wants to sit in the seat such that the distance between him and the closest person to him is maximized.
+ * Return that maximum distance to closest person.
+ *
+ * Example 1:
+ * Input: [1,0,0,0,1,0,1]
+ * Output: 2
+ * Explanation:
+ * If Alex sits in the second open seat (seats[2]), then the closest person has distance 2.
+ * If Alex sits in any other open seat, the closest person has distance 1.
+ * Thus, the maximum distance to the closest person is 2.
+ *
+ * Example 2:
+ * Input: [1,0,0,0]
+ * Output: 3
+ * Explanation:
+ * If Alex sits in the last seat, the closest person is 3 seats away.
+ * This is the maximum distance possible, so the answer is 3.
+ * Note:
+ *
+ * 1 <= seats.length <= 20000
+ * seats contains only 0s or 1s, at least one 0, and at least one 1.
+ * */
+public class _849 {
+    public static class Solution1 {
+        int maxDist = 0;
+        public int maxDistToClosest(int[] seats) {
+            for (int i = 0; i < seats.length; i++) {
+                if (seats[i] == 0) {
+                    extend(seats, i);
+                }
+            }
+            return maxDist;
+        }
+
+        private void extend(int[] seats, int position) {
+            int left = position - 1;
+            int right = position + 1;
+            int leftMinDistance = 1;
+            while (left >= 0) {
+                if (seats[left] == 0) {
+                    leftMinDistance++;
+                    left--;
+                } else {
+                    break;
+                }
+            }
+            int rightMinDistance = 1;
+            while (right < seats.length) {
+                if (seats[right] == 0) {
+                    rightMinDistance++;
+                    right++;
+                } else {
+                    break;
+                }
+            }
+            int maxReach = 0;
+            if (position == 0) {
+                maxReach = rightMinDistance;
+            } else if (position == seats.length - 1) {
+                maxReach = leftMinDistance;
+            } else {
+                maxReach = Math.min(leftMinDistance, rightMinDistance);
+            }
+            maxDist = Math.max(maxDist, maxReach);
+        }
+    }
+}

src/test/java/com/fishercoder/_849Test.java

@@ -0,0 +1,27 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._849;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _849Test {
+
+    private static _849.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _849.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(2, solution1.maxDistToClosest(new int[]{1, 0, 0, 0, 1, 0, 1}));
+    }
+
+    @Test
+    public void test2() {
+        assertEquals(3, solution1.maxDistToClosest(new int[]{1, 0, 0, 0}));
+    }
+}