Solution.cs

public class Solution {
    public int MakeArrayIncreasing(int[] arr1, int[] arr2) {
        Array.Sort(arr2);
        int m = 0;
        foreach (int x in arr2) {
            if (m == 0 || x != arr2[m - 1]) {
                arr2[m++] = x;
            }
        }
        int inf = 1 << 30;
        int[] arr = new int[arr1.Length + 2];
        arr[0] = -inf;
        arr[arr.Length - 1] = inf;
        for (int i = 0; i < arr1.Length; ++i) {
            arr[i + 1] = arr1[i];
        }
        int[] f = new int[arr.Length];
        Array.Fill(f, inf);
        f[0] = 0;
        for (int i = 1; i < arr.Length; ++i) {
            if (arr[i - 1] < arr[i]) {
                f[i] = f[i - 1];
            }
            int j = search(arr2, arr[i], m);
            for (int k = 1; k <= Math.Min(i - 1, j); ++k) {
                if (arr[i - k - 1] < arr2[j - k]) {
                    f[i] = Math.Min(f[i], f[i - k - 1] + k);
                }
            }
        }
        return f[arr.Length - 1] >= inf ? -1 : f[arr.Length - 1];
    }

    private int search(int[] nums, int x, int n) {
        int l = 0, r = n;
        while (l < r) {
            int mid = (l + r) >> 1;
            if (nums[mid] >= x) {
                r = mid;
            } else {
                l = mid + 1;
            }
        }
        return l;
    }
}