add 1289

fishercoder1534 · fishercoder1534 · commit 1bb4a97817a6 · 2020-02-26T17:26:34.000-08:00
diff --git a/README.md b/README.md
@@ -50,6 +50,7 @@ _If you like this project, please leave me a star._ &#9733;
 |1295|[Find Numbers with Even Number of Digits](https://leetcode.com/problems/find-numbers-with-even-number-of-digits/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1295.java) | [:tv:](https://youtu.be/HRp8mNJvLZ0) |Easy||
 |1291|[Sequential Digits](https://leetcode.com/problems/sequential-digits/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1291.java) |  |Medium||
 |1290|[Convert Binary Number in a Linked List to Integer](https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1290.java) |  |Easy||
+|1289|[Minimum Falling Path Sum II](https://leetcode.com/problems/minimum-falling-path-sum-ii/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1289.java) |  |Hard|Dynamic Programming|
 |1287|[Element Appearing More Than 25% In Sorted Array](https://leetcode.com/problems/element-appearing-more-than-25-in-sorted-array/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1287.java) | [:tv:](https://youtu.be/G74W8v2yVjY) |Easy||
 |1286|[Iterator for Combination](https://leetcode.com/problems/iterator-for-combination/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1286.java) | |Medium|Backtracking, Design|
 |1282|[Group the People Given the Group Size They Belong To](https://leetcode.com/problems/group-the-people-given-the-group-size-they-belong-to/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1282.java) |   [:tv:](https://www.youtube.com/watch?v=wGgcRCpSAa8)|Medium||
diff --git a/src/main/java/com/fishercoder/solutions/_1289.java b/src/main/java/com/fishercoder/solutions/_1289.java
@@ -0,0 +1,51 @@
+package com.fishercoder.solutions;
+
+/**
+ * 1289. Minimum Falling Path Sum II
+ *
+ * Given a square grid of integers arr, a falling path with non-zero shifts is a
+ * choice of exactly one element from each row of arr, such that no two elements chosen in adjacent rows are in the same column.
+ * Return the minimum sum of a falling path with non-zero shifts.
+ *
+ * Example 1:
+ * Input: arr = [[1,2,3],[4,5,6],[7,8,9]]
+ * Output: 13
+ * Explanation:
+ * The possible falling paths are:
+ * [1,5,9], [1,5,7], [1,6,7], [1,6,8],
+ * [2,4,8], [2,4,9], [2,6,7], [2,6,8],
+ * [3,4,8], [3,4,9], [3,5,7], [3,5,9]
+ * The falling path with the smallest sum is [1,5,7], so the answer is 13.
+ *
+ * Constraints:
+ * 1 <= arr.length == arr[i].length <= 200
+ * -99 <= arr[i][j] <= 99
+ * */
+public class _1289 {
+    public static class Solution1 {
+        public int minFallingPathSum(int[][] arr) {
+            int size = arr.length;
+            int[][] dp = new int[size][size];
+            for (int i = 0; i < size; i++) {
+                for (int j = 0; j < size; j++) {
+                    if (i == 0) {
+                        dp[i][j] = arr[i][j];
+                    } else {
+                        int previousRowMin = Integer.MAX_VALUE;
+                        for (int k = 0; k < size; k++) {
+                            if (k != j) {
+                                previousRowMin = Math.min(dp[i - 1][k], previousRowMin);
+                            }
+                        }
+                        dp[i][j] = arr[i][j] + previousRowMin;
+                    }
+                }
+            }
+            int result = dp[size - 1][size - 1];
+            for (int i = 0; i < size; i++) {
+                result = Math.min(result, dp[size - 1][i]);
+            }
+            return result;
+        }
+    }
+}
diff --git a/src/test/java/com/fishercoder/_1289Test.java b/src/test/java/com/fishercoder/_1289Test.java
@@ -0,0 +1,28 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1289;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static junit.framework.TestCase.assertEquals;
+
+public class _1289Test {
+    private static _1289.Solution1 solution1;
+    private static int[][] arr;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1289.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        arr = new int[][]{
+                {1, 2, 3},
+                {4, 5, 6},
+                {7, 8, 9}
+        };
+        assertEquals(13, solution1.minFallingPathSum(arr));
+    }
+
+}
