BasketballExercise.java

/**
 * https://codeforces.com/problemset/problem/1195/C #dynamic-programming #refactor
 *
 * <p>better idea: - chon 0 - chon 1 - khong chon
 *
 * <p>sum[0][j] : max sum chon dong 0 cot j sum[1][j] : max sum chon dong 1 cot j sum[2][j] : max
 * sum khong chon cot j
 *
 * <p>sum[0][j] = arr[0][j] + Math.max(sum[1][j-1], sum[2][j-1]) sum[1][j] = arr[1][j] +
 * Math.max(sum[0][j-1], sum[2][j-1]) sum[2][j] = Math.max(sum[0][j-1], sum[1][j-1])
 *
 * <p>for (int j = 1; j <= n; j++) { for (int i = 0; i < 2; i++) { sum[i][j] =
 * Math.max(sum[1-i][j-1] + arr[i][j], sum[i][j-1]); } } result = Math.max(sum[0][n], sum[1][n]);
 */
import java.util.Scanner;

public class BasketballExercise {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    int n = sc.nextInt();
    long[][] arr = new long[2][n + 1];
    for (int i = 0; i < 2; i++) {
      for (int j = 1; j <= n; j++) {
        arr[i][j] = sc.nextLong();
      }
    }

    long[][] sum = new long[2][n + 1];
    sum[0][1] = arr[0][1];
    sum[1][1] = arr[1][1];
    for (int j = 2; j <= n; j++) {
      for (int i = 0; i < 2; i++) {
        sum[i][j] = Math.max(sum[1 - i][j - 1], Math.max(sum[i][j - 2], sum[1 - i][j - 2]));
        sum[i][j] += arr[i][j];
      }
    }

    long result = Math.max(sum[0][n], sum[1][n]);
    if (n > 1) {
      result = Math.max(result, Math.max(sum[0][n - 1], sum[1][n - 1]));
    }
    System.out.println(result);
  }
}