package class45;

// 测试链接: https://leetcode.com/problems/create-maximum-number/
public class Code02_CreateMaximumNumber {

	public static int[] maxNumber1(int[] nums1, int[] nums2, int k) {
		int len1 = nums1.length;
		int len2 = nums2.length;
		if (k < 0 || k > len1 + len2) {
			return null;
		}
		int[] res = new int[k];
		int[][] dp1 = getdp(nums1); // 生成dp1这个表，以后从nums1中，只要固定拿N个数，
		int[][] dp2 = getdp(nums2);
		// get1 从arr1里拿的数量
		// K - get1 从arr2里拿的数量
		for (int get1 = Math.max(0, k - len2); get1 <= Math.min(k, len1); get1++) {
			// arr1 挑 get1个，怎么得到一个最优结果
			int[] pick1 = maxPick(nums1, dp1, get1);
			int[] pick2 = maxPick(nums2, dp2, k - get1);
			int[] merge = merge(pick1, pick2);
			res = preMoreThanLast(res, 0, merge, 0) ? res : merge;
		}
		return res;
	}

	public static int[] merge(int[] nums1, int[] nums2) {
		int k = nums1.length + nums2.length;
		int[] ans = new int[k];
		for (int i = 0, j = 0, r = 0; r < k; ++r) {
			ans[r] = preMoreThanLast(nums1, i, nums2, j) ? nums1[i++] : nums2[j++];
		}
		return ans;
	}

	public static boolean preMoreThanLast(int[] nums1, int i, int[] nums2, int j) {
		while (i < nums1.length && j < nums2.length && nums1[i] == nums2[j]) {
			i++;
			j++;
		}
		return j == nums2.length || (i < nums1.length && nums1[i] > nums2[j]);
	}

	public static int[] maxNumber2(int[] nums1, int[] nums2, int k) {
		int len1 = nums1.length;
		int len2 = nums2.length;
		if (k < 0 || k > len1 + len2) {
			return null;
		}
		int[] res = new int[k];
		int[][] dp1 = getdp(nums1);
		int[][] dp2 = getdp(nums2);
		for (int get1 = Math.max(0, k - len2); get1 <= Math.min(k, len1); get1++) {
			int[] pick1 = maxPick(nums1, dp1, get1);
			int[] pick2 = maxPick(nums2, dp2, k - get1);
			int[] merge = mergeBySuffixArray(pick1, pick2);
			res = moreThan(res, merge) ? res : merge;
		}
		return res;
	}

	public static boolean moreThan(int[] pre, int[] last) {
		int i = 0;
		int j = 0;
		while (i < pre.length && j < last.length && pre[i] == last[j]) {
			i++;
			j++;
		}
		return j == last.length || (i < pre.length && pre[i] > last[j]);
	}

	public static int[] mergeBySuffixArray(int[] nums1, int[] nums2) {
		int size1 = nums1.length;
		int size2 = nums2.length;
		int[] nums = new int[size1 + 1 + size2];
		for (int i = 0; i < size1; i++) {
			nums[i] = nums1[i] + 2;
		}
		nums[size1] = 1;
		for (int j = 0; j < size2; j++) {
			nums[j + size1 + 1] = nums2[j] + 2;
		}
		DC3 dc3 = new DC3(nums, 11);
		int[] rank = dc3.rank;
		int[] ans = new int[size1 + size2];
		int i = 0;
		int j = 0;
		int r = 0;
		while (i < size1 && j < size2) {
			ans[r++] = rank[i] > rank[j + size1 + 1] ? nums1[i++] : nums2[j++];
		}
		while (i < size1) {
			ans[r++] = nums1[i++];
		}
		while (j < size2) {
			ans[r++] = nums2[j++];
		}
		return ans;
	}

	public static class DC3 {

		public int[] sa;

		public int[] rank;

		public DC3(int[] nums, int max) {
			sa = sa(nums, max);
			rank = rank();
		}

		private int[] sa(int[] nums, int max) {
			int n = nums.length;
			int[] arr = new int[n + 3];
			for (int i = 0; i < n; i++) {
				arr[i] = nums[i];
			}
			return skew(arr, n, max);
		}

		private int[] skew(int[] nums, int n, int K) {
			int n0 = (n + 2) / 3, n1 = (n + 1) / 3, n2 = n / 3, n02 = n0 + n2;
			int[] s12 = new int[n02 + 3], sa12 = new int[n02 + 3];
			for (int i = 0, j = 0; i < n + (n0 - n1); ++i) {
				if (0 != i % 3) {
					s12[j++] = i;
				}
			}
			radixPass(nums, s12, sa12, 2, n02, K);
			radixPass(nums, sa12, s12, 1, n02, K);
			radixPass(nums, s12, sa12, 0, n02, K);
			int name = 0, c0 = -1, c1 = -1, c2 = -1;
			for (int i = 0; i < n02; ++i) {
				if (c0 != nums[sa12[i]] || c1 != nums[sa12[i] + 1] || c2 != nums[sa12[i] + 2]) {
					name++;
					c0 = nums[sa12[i]];
					c1 = nums[sa12[i] + 1];
					c2 = nums[sa12[i] + 2];
				}
				if (1 == sa12[i] % 3) {
					s12[sa12[i] / 3] = name;
				} else {
					s12[sa12[i] / 3 + n0] = name;
				}
			}
			if (name < n02) {
				sa12 = skew(s12, n02, name);
				for (int i = 0; i < n02; i++) {
					s12[sa12[i]] = i + 1;
				}
			} else {
				for (int i = 0; i < n02; i++) {
					sa12[s12[i] - 1] = i;
				}
			}
			int[] s0 = new int[n0], sa0 = new int[n0];
			for (int i = 0, j = 0; i < n02; i++) {
				if (sa12[i] < n0) {
					s0[j++] = 3 * sa12[i];
				}
			}
			radixPass(nums, s0, sa0, 0, n0, K);
			int[] sa = new int[n];
			for (int p = 0, t = n0 - n1, k = 0; k < n; k++) {
				int i = sa12[t] < n0 ? sa12[t] * 3 + 1 : (sa12[t] - n0) * 3 + 2;
				int j = sa0[p];
				if (sa12[t] < n0 ? leq(nums[i], s12[sa12[t] + n0], nums[j], s12[j / 3])
						: leq(nums[i], nums[i + 1], s12[sa12[t] - n0 + 1], nums[j], nums[j + 1], s12[j / 3 + n0])) {
					sa[k] = i;
					t++;
					if (t == n02) {
						for (k++; p < n0; p++, k++) {
							sa[k] = sa0[p];
						}
					}
				} else {
					sa[k] = j;
					p++;
					if (p == n0) {
						for (k++; t < n02; t++, k++) {
							sa[k] = sa12[t] < n0 ? sa12[t] * 3 + 1 : (sa12[t] - n0) * 3 + 2;
						}
					}
				}
			}
			return sa;
		}

		private void radixPass(int[] nums, int[] input, int[] output, int offset, int n, int k) {
			int[] cnt = new int[k + 1];
			for (int i = 0; i < n; ++i) {
				cnt[nums[input[i] + offset]]++;
			}
			for (int i = 0, sum = 0; i < cnt.length; ++i) {
				int t = cnt[i];
				cnt[i] = sum;
				sum += t;
			}
			for (int i = 0; i < n; ++i) {
				output[cnt[nums[input[i] + offset]]++] = input[i];
			}
		}

		private boolean leq(int a1, int a2, int b1, int b2) {
			return a1 < b1 || (a1 == b1 && a2 <= b2);
		}

		private boolean leq(int a1, int a2, int a3, int b1, int b2, int b3) {
			return a1 < b1 || (a1 == b1 && leq(a2, a3, b2, b3));
		}

		private int[] rank() {
			int n = sa.length;
			int[] ans = new int[n];
			for (int i = 0; i < n; i++) {
				ans[sa[i]] = i;
			}
			return ans;
		}

	}

	public static int[][] getdp(int[] arr) {
		int size = arr.length; // 0~N-1
		int pick = arr.length + 1; // 1 ~ N
		int[][] dp = new int[size][pick];
		// get 不从0开始，因为拿0个无意义
		for (int get = 1; get < pick; get++) { // 1 ~ N
			int maxIndex = size - get;
			// i~N-1
			for (int i = size - get; i >= 0; i--) {
				if (arr[i] >= arr[maxIndex]) {
					maxIndex = i;
				}
				dp[i][get] = maxIndex;
			}
		}
		return dp;
	}

	public static int[] maxPick(int[] arr, int[][] dp, int pick) {
		int[] res = new int[pick];
		for (int resIndex = 0, dpRow = 0; pick > 0; pick--, resIndex++) {
			res[resIndex] = arr[dp[dpRow][pick]];
			dpRow = dp[dpRow][pick] + 1;
		}
		return res;
	}

}