[N-0] add 723

fishercoder1534 · fishercoder1534 · commit f0d39ed407e7 · 2017-11-07T08:34:41.000-08:00
diff --git a/README.md b/README.md
@@ -22,6 +22,7 @@ Your ideas/fixes/algorithms are more than welcome!
 
 |  #  |      Title     |   Solutions   | Time          | Space         | Difficulty  | Tag          | Notes
 |-----|----------------|---------------|---------------|---------------|-------------|--------------|-----
+|723|[Candy Crush](https://leetcode.com/problems/candy-crush/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_723.java) | O((r*c)^2) | O((r*c)) | Medium | Array, Two Pointers
 |721|[Accounts Merge](https://leetcode.com/problems/accounts-merge/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_721.java) |  | | Medium | DFS, Union Find
 |720|[Longest Word in Dictionary](https://leetcode.com/problems/longest-word-in-dictionary/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_720.java) | O(∑wi) where wi is the length of words[i] | O(∑wi) where wi is the length of words[i] | Easy | Trie
 |719|[Find K-th Smallest Pair Distance](https://leetcode.com/problems/find-k-th-smallest-pair-distance/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_719.java) | O(nlogw + nlogn) | O(1) | Hard | Binary Search
diff --git a/src/main/java/com/fishercoder/solutions/_723.java b/src/main/java/com/fishercoder/solutions/_723.java
@@ -38,8 +38,45 @@
  */
 public class _723 {
     public static class Solution1 {
+        /**credit: https://leetcode.com/articles/candy-crush/*/
         public int[][] candyCrush(int[][] board) {
-            return null;
+            int row = board.length;
+            int col = board[0].length;
+            boolean todo = false;
+            for (int i = 0; i < row; i++) {
+                for (int j = 0; j < col - 2; j++) {
+                    int v = Math.abs(board[i][j]);
+                    if (v != 0 && v == Math.abs(board[i][j + 1]) && v == Math.abs(board[i][j + 2])) {
+                        //mark all of them to be negative
+                        board[i][j] = board[i][j + 1] = board[i][j + 2] = -v;
+                        todo = true;
+                    }
+                }
+            }
+
+            for (int i = 0; i < row - 2; i++) {
+                for (int j = 0; j < col; j++) {
+                    int v = Math.abs(board[i][j]);
+                    if (v != 0 && v == Math.abs(board[i + 1][j]) && v == Math.abs(board[i + 2][j])) {
+                        board[i + 1][j] = board[i + 2][j] = board[i][j] = -v;
+                        todo = true;
+                    }
+                }
+            }
+
+            for (int j = 0; j < col; j++) {
+                int wr = row - 1;
+                for (int i = row - 1; i >= 0; i--) {
+                    if (board[i][j] > 0) {
+                        board[wr--][j] = board[i][j];
+                    }
+                }
+                while (wr >= 0) {
+                    board[wr--][j] = 0;
+                }
+            }
+
+            return todo ? candyCrush(board) : board;
         }
     }
 }
diff --git a/src/test/java/com/fishercoder/_723Test.java b/src/test/java/com/fishercoder/_723Test.java
@@ -0,0 +1,55 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._723;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertArrayEquals;
+
+public class _723Test {
+    private static _723.Solution1 solution1;
+    private static int[][] board;
+    private static int[][] expected;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _723.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        board = new int[][]{
+                {110, 5, 112, 113, 114},
+                {210, 211, 5, 213, 214},
+                {310, 311, 3, 313, 314},
+                {410, 411, 412, 5, 414},
+                {5, 1, 512, 3, 3},
+                {610, 4, 1, 613, 614},
+                {710, 1, 2, 713, 714},
+                {810, 1, 2, 1, 1},
+                {1, 1, 2, 2, 2},
+                {4, 1, 4, 4, 1014},
+        };
+
+        expected = new int[][]{
+                {0, 0, 0, 0, 0},
+                {0, 0, 0, 0, 0},
+                {0, 0, 0, 0, 0},
+                {110, 0, 0, 0, 114},
+                {210, 0, 0, 0, 214},
+                {310, 0, 0, 113, 314},
+                {410, 0, 0, 213, 414},
+                {610, 211, 112, 313, 614},
+                {710, 311, 412, 613, 714},
+                {810, 411, 512, 713, 1014}
+        };
+        assert2dArrayEquals(expected, solution1.candyCrush(board));
+    }
+
+    private void assert2dArrayEquals(int[][] expected, int[][] actual) {
+        for (int i = 0; i < expected.length; i++) {
+            assertArrayEquals(expected[i], actual[i]);
+        }
+    }
+
+}
