modify code

Author: algorithmzuo

src/class46/Code02_RemoveBoxes.java

@@ -3,24 +3,54 @@
 // 本题测试链接 : https://leetcode.com/problems/remove-boxes/
 public class Code02_RemoveBoxes {
 
-public static int removeBoxes(int[] boxes) {
+public static int removeBoxes1(int[] boxes) {
 int N = boxes.length;
 int[][][] dp = new int[N][N][N];
-int ans = process(boxes, 0, N - 1, 0, dp);
+int ans = process1(boxes, 0, N - 1, 0, dp);
 return ans;
 }
 
-public static int process(int[] boxes, int L, int R, int K, int[][][] dp) {
+public static int process1(int[] boxes, int L, int R, int K, int[][][] dp) {
 if (L > R) {
 return 0;
 }
 if (dp[L][R][K] > 0) {
 return dp[L][R][K];
 }
-int ans = process(boxes, L + 1, R, 0, dp) + (K + 1) * (K + 1);
+int ans = process1(boxes, L + 1, R, 0, dp) + (K + 1) * (K + 1);
 for (int i = L + 1; i <= R; i++) {
 if (boxes[i] == boxes[L]) {
-ans = Math.max(ans, process(boxes, L + 1, i - 1, 0, dp) + process(boxes, i, R, K + 1, dp));
+ans = Math.max(ans, process1(boxes, L + 1, i - 1, 0, dp) + process1(boxes, i, R, K + 1, dp));
+}
+}
+dp[L][R][K] = ans;
+return ans;
+}
+
+public static int removeBoxes2(int[] boxes) {
+int N = boxes.length;
+int[][][] dp = new int[N][N][N];
+int ans = process2(boxes, 0, N - 1, 0, dp);
+return ans;
+}
+
+public static int process2(int[] boxes, int L, int R, int K, int[][][] dp) {
+if (L > R) {
+return K * K;
+}
+if (dp[L][R][K] > 0) {
+return dp[L][R][K];
+}
+int ans = 0;
+int last = L;
+while (last + 1 <= R && boxes[last + 1] == boxes[L]) {
+last++;
+}
+int pre = K + last - L;
+ans = (pre + 1) * (pre + 1) + process2(boxes, last + 1, R, 0, dp);
+for (int i = last + 2; i <= R; i++) {
+if (boxes[i] == boxes[L] && boxes[i - 1] != boxes[L]) {
+ans = Math.max(ans, process2(boxes, last + 1, i - 1, 0, dp) + process2(boxes, i, R, pre + 1, dp));
 }
 }
 dp[L][R][K] = ans;