add 849 java

Author: yennanliu

README.md

@@ -287,7 +287,7 @@
 840 | [Magic Squares In Grid](https://leetcode.com/problems/magic-squares-in-grid/) | [Python](./leetcode_python/Array/magic-squares-in-grid.py) | _O(m * n)_ | _O(1)_ | Easy |`complex`| AGAIN (not start)
 842 | [Split Array into Fibonacci Sequence](https://leetcode.com/problems/split-array-into-fibonacci-sequence/) | [Python](./leetcode_python/Array/split-array-into-fibonacci-sequence.py) | _O(n^3)_ | _O(n)_ | Medium |check `# 306 Addictive Number`, `basic`, `dfs`, `fibonacci`| AGAIN* (not start)
 845 | [Longest Mountain in Array](https://leetcode.com/problems/longest-mountain-in-array/) | [Python](./leetcode_python/Array/longest-mountain-in-array.py) | _O(n)_ | _O(1)_ | Medium |`basic`, `trick`| AGAIN* (not start) 
-849 | [Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person/) | [Python](./leetcode_python/Array/maximize-distance-to-closest-person.py) | _O(n)_ | _O(1)_ | Easy |`basic`, `trick`| AGAIN (not start*)
+849 | [Maximize Distance to Closest Person](https://leetcode.com/problems/maximize-distance-to-closest-person/) | [Python](./leetcode_python/Array/maximize-distance-to-closest-person.py), [Java](./leetcode_java/src/main/java/LeetCodeJava/Array/MaximizeDistanceToClosestPerson.java) | _O(n)_ | _O(1)_ | Easy |`basic`, google, 2 pointers| AGAIN (1)
 860 | [Lemonade Change](https://leetcode.com/problems/lemonade-change/) | [Python](./leetcode_python/Array/lemonade-change.py) | _O(n)_ | _O(1)_ | Easy |amazon| OK* (2)
 0868 | [Transpose Matrix](https://leetcode.com/problems/transpose-matrix/) | [Python](./leetcode_python/Array/transpose-matrix.py) | _O(r * c)_ | _O(1)_ | Easy |`basic`| OK*
 885 | [Spiral Matrix III](https://leetcode.com/problems/spiral-matrix-iii/) | [Python](./leetcode_python/Array/spiral-matrix-iii.py) | _O(max(m, n)^2)_ | _O(1)_ | Medium  |`basic`| AGAIN* (not start)

data/progress.txt

@@ -1,4 +1,4 @@
-20241227: 079,212(todo),362
+20241227: 079,212(todo),362,849
 20241222: 369,311
 20241221: 370
 20241220: 815,871,593,1109

data/to_review.txt

@@ -1,32 +1,32 @@
-2025-02-20 -> ['079,212(todo),362']
+2025-02-20 -> ['079,212(todo),362,849']
 2025-02-15 -> ['369,311']
 2025-02-14 -> ['370']
 2025-02-13 -> ['815,871,593,1109']
 2025-02-07 -> ['560,523']
 2025-02-01 -> ['304,853,325']
-2025-01-30 -> ['079,212(todo),362']
+2025-01-30 -> ['079,212(todo),362,849']
 2025-01-26 -> ['370(todo)']
 2025-01-25 -> ['369,311']
 2025-01-24 -> ['370', '34,767']
 2025-01-23 -> ['815,871,593,1109']
 2025-01-20 -> ['722,380']
 2025-01-19 -> ['33,81']
-2025-01-17 -> ['079,212(todo),362', '560,523', '253']
+2025-01-17 -> ['079,212(todo),362,849', '560,523', '253']
 2025-01-16 -> ['776,31']
 2025-01-15 -> ['004(todo),34(todo),162(todo),275(todo)']
 2025-01-14 -> ['986(todo),1229(todo),1868(todo),80(todo),209(todo),283(todo),360(todo),713(todo),532(todo),611(todo)']
 2025-01-12 -> ['369,311']
 2025-01-11 -> ['370', '304,853,325', '394']
 2025-01-10 -> ['815,871,593,1109', '833,950']
-2025-01-09 -> ['079,212(todo),362']
+2025-01-09 -> ['079,212(todo),362,849']
 2025-01-05 -> ['370(todo)']
-2025-01-04 -> ['079,212(todo),362', '369,311', '560,523', '53,210,207']
+2025-01-04 -> ['079,212(todo),362,849', '369,311', '560,523', '53,210,207']
 2025-01-03 -> ['370', '34,767', '444']
 2025-01-02 -> ['815,871,593,1109', '1188,130,855(again)']
-2025-01-01 -> ['079,212(todo),362']
-2024-12-30 -> ['079,212(todo),362', '369,311', '722,380']
-2024-12-29 -> ['079,212(todo),362', '370', '304,853,325', '33,81']
-2024-12-28 -> ['079,212(todo),362', '815,871,593,1109', '900']
+2025-01-01 -> ['079,212(todo),362,849']
+2024-12-30 -> ['079,212(todo),362,849', '369,311', '722,380']
+2024-12-29 -> ['079,212(todo),362,849', '370', '304,853,325', '33,81']
+2024-12-28 -> ['079,212(todo),362,849', '815,871,593,1109', '900']
 2024-12-27 -> ['369,311', '560,523', '253', '26,27', '802,1197,26']
 2024-12-26 -> ['370', '776,31']
 2024-12-25 -> ['369,311', '815,871,593,1109', '004(todo),34(todo),162(todo),275(todo)']

leetcode_java/src/main/java/LeetCodeJava/Array/MaximizeDistanceToClosestPerson.java

@@ -0,0 +1,140 @@
+package LeetCodeJava.Array;
+
+// https://leetcode.com/problems/maximize-distance-to-closest-person/description/
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+/**
+ * 849. Maximize Distance to Closest Person
+ * Medium
+ * Topics
+ * Companies
+ * You are given an array representing a row of seats where seats[i] = 1 represents a person sitting in the ith seat, and seats[i] = 0 represents that the ith seat is empty (0-indexed).
+ *
+ * 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 the closest person.
+ *
+ *
+ *
+ * Example 1:
+ *
+ *
+ * Input: seats = [1,0,0,0,1,0,1]
+ * Output: 2
+ * Explanation:
+ * If Alex sits in the second open seat (i.e. 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: seats = [1,0,0,0]
+ * Output: 3
+ * Explanation:
+ * If Alex sits in the last seat (i.e. seats[3]), the closest person is 3 seats away.
+ * This is the maximum distance possible, so the answer is 3.
+ * Example 3:
+ *
+ * Input: seats = [0,1]
+ * Output: 1
+ *
+ *
+ * Constraints:
+ *
+ * 2 <= seats.length <= 2 * 104
+ * seats[i] is 0 or 1.
+ * At least one seat is empty.
+ * At least one seat is occupied.
+ *
+ */
+public class MaximizeDistanceToClosestPerson {
+
+    // V0
+    // TODO : fix below
+//    public int maxDistToClosest(int[] seats) {
+//
+//        List<Integer> distances = new ArrayList<>();
+//        int lastIdx = -1;
+//        for(int i = seats.length - 1; i >= 0; i--){
+//            if (seats[i] == 1){
+//                if (lastIdx != -1){
+//                    int diff = Math.abs(i - lastIdx);
+//                    distances.add(diff);
+//                }
+//                lastIdx = i;
+//            }
+//        }
+//
+//        System.out.println(">>> (before sort) distances = " + distances);
+//        distances.sort(Integer::compareTo);
+//        System.out.println(">>> (after sort) distances = " + distances);
+//
+//        // edge case : if only one "1"
+//        if (distances.isEmpty()){
+//            return seats.length-1;
+//        }
+//        // return the max dist
+//        return distances.get(distances.size()-1) / 2; // ??
+//    }
+
+    // V1-1
+    // IDEA : Next Array
+    // https://leetcode.com/problems/maximize-distance-to-closest-person/editorial/
+    public int maxDistToClosest_1_1(int[] seats) {
+        int N = seats.length;
+        int[] left = new int[N], right = new int[N];
+        Arrays.fill(left, N);
+        Arrays.fill(right, N);
+
+        for (int i = 0; i < N; ++i) {
+            if (seats[i] == 1)
+                left[i] = 0;
+            else if (i > 0)
+                left[i] = left[i - 1] + 1;
+        }
+
+        for (int i = N - 1; i >= 0; --i) {
+            if (seats[i] == 1)
+                right[i] = 0;
+            else if (i < N - 1)
+                right[i] = right[i + 1] + 1;
+        }
+
+        int ans = 0;
+        for (int i = 0; i < N; ++i)
+            if (seats[i] == 0)
+                ans = Math.max(ans, Math.min(left[i], right[i]));
+        return ans;
+    }
+
+
+    // V1-2
+    // IDEA : 2 POINTERS
+    // https://leetcode.com/problems/maximize-distance-to-closest-person/editorial/
+    public int maxDistToClosest_1_2(int[] seats) {
+        int N = seats.length;
+        int prev = -1, future = 0;
+        int ans = 0;
+
+        for (int i = 0; i < N; ++i) {
+            if (seats[i] == 1) {
+                prev = i;
+            } else {
+                while (future < N && seats[future] == 0 || future < i)
+                    future++;
+
+                int left = prev == -1 ? N : i - prev;
+                int right = future == N ? N : future - i;
+                ans = Math.max(ans, Math.min(left, right));
+            }
+        }
+
+        return ans;
+    }
+
+    // V2
+}

leetcode_java/src/main/java/dev/workspace6.java

@@ -700,4 +700,60 @@ public int getHits(int timestamp) {
         }
     }
 
+  // LC 849
+  // https://leetcode.com/problems/maximize-distance-to-closest-person/
+  // 4.10 pm - 4.20 pm
+  /**
+   *
+   * 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 the closest person.
+   *
+   */
+  /**
+   *
+   * Idea :
+   *
+   *  array collect cur distances ? (dist between "1", and "1") ???
+   *  sorting the distance
+   *  select the "max" distance
+   *
+   *
+   * Exp 1:
+   *
+   * Input: seats = [1,0,0,0,1,0,1]
+   * Output: 2
+   *
+   * ->
+   *
+   *
+   */
+  public int maxDistToClosest(int[] seats) {
+
+      List<Integer> distances = new ArrayList<>();
+      int lastIdx = -1;
+      for(int i = seats.length - 1; i >= 0; i--){
+          if (seats[i] == 1){
+              if (lastIdx != -1){
+                  int diff = Math.abs(i - lastIdx);
+                  distances.add(diff);
+              }
+              lastIdx = i;
+          }
+      }
+
+      System.out.println(">>> (before sort) distances = " + distances);
+      distances.sort(Integer::compareTo);
+      System.out.println(">>> (after sort) distances = " + distances);
+
+      // edge case : if only one "1"
+      if (distances.isEmpty()){
+          return seats.length-1;
+      }
+      // return the max dist
+      return distances.get(distances.size()-1) / 2; // ??
+    }
+
 }