Add 1690 (#140)

WillShen7789 · web-flow · commit ba5cfebc1bed · 2020-12-20T09:54:48.000-08:00
* Add 1690

* Fix checkstyleMain
diff --git a/src/main/java/com/fishercoder/solutions/_1690.java b/src/main/java/com/fishercoder/solutions/_1690.java
@@ -0,0 +1,46 @@
+package com.fishercoder.solutions;
+
+public class _1690 {
+    public static class Solution1 {
+
+        int[] stonesRef;
+
+        int[] prepareSums;
+
+        int[][] maxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ = new int[1005][1005];
+
+        public int stoneGameVII(int[] stones) {
+            this.stonesRef = stones;
+            int totalStonesNumber = stones.length;
+            this.prepareSums = new int[totalStonesNumber + 1];
+            for (int i = 1; i <= totalStonesNumber; i++) {
+                this.prepareSums[i] = this.prepareSums[i - 1] + stones[i - 1];
+            }
+            for (int len = 1; len <= totalStonesNumber; len++) {
+                for (int i = 1; i + len - 1 <= totalStonesNumber; i++) {
+                    int j = i + len - 1;
+                    this.setMaxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ(i, j);
+                }
+            }
+            return maxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ[1][totalStonesNumber];
+        }
+
+        private void setMaxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ(int i, int j) {
+            if (j - i == 0) {
+                maxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ[i][j] = 0;
+            } else if (j - i == 1) {
+                maxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ[i][j] = Math.max(stonesRef[i - 1], stonesRef[j - 1]);
+            } else {
+                maxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ[i][j] = Math.max(
+                        this.sumOfTheStonesValueInPosIToJ(i + 1, j)
+                                - maxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ[i + 1][j],
+                        this.sumOfTheStonesValueInPosIToJ(i, j - 1)
+                                - maxDiffScoureBetweenTowPlayerWhenPlayInPosItoJ[i][j - 1]);
+            }
+        }
+
+        private int sumOfTheStonesValueInPosIToJ(int i, int j) {
+            return this.prepareSums[j] - this.prepareSums[i - 1];
+        }
+    }
+}
diff --git a/src/test/java/com/fishercoder/_1690Test.java b/src/test/java/com/fishercoder/_1690Test.java
@@ -0,0 +1,22 @@
+package com.fishercoder;
+
+import com.fishercoder.solutions._1690;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class _1690Test {
+    private static _1690.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1690.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        assertEquals(6, solution1.stoneGameVII(new int[]{5,3,1,4,2}));
+    }
+
+}
