<p>Given two integer arrays&nbsp;<code>arr1</code> and <code>arr2</code>, return the minimum number of operations (possibly zero) needed&nbsp;to make <code>arr1</code> strictly increasing.</p>

<p>In one operation, you can choose two indices&nbsp;<code>0 &lt;=&nbsp;i &lt; arr1.length</code>&nbsp;and&nbsp;<code>0 &lt;= j &lt; arr2.length</code>&nbsp;and do the assignment&nbsp;<code>arr1[i] = arr2[j]</code>.</p>

<p>If there is no way to make&nbsp;<code>arr1</code>&nbsp;strictly increasing,&nbsp;return&nbsp;<code>-1</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> arr1 = [1,5,3,6,7], arr2 = [1,3,2,4]
<strong>Output:</strong> 1
<strong>Explanation:</strong> Replace <code>5</code> with <code>2</code>, then <code>arr1 = [1, 2, 3, 6, 7]</code>.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> arr1 = [1,5,3,6,7], arr2 = [4,3,1]
<strong>Output:</strong> 2
<strong>Explanation:</strong> Replace <code>5</code> with <code>3</code> and then replace <code>3</code> with <code>4</code>. <code>arr1 = [1, 3, 4, 6, 7]</code>.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> arr1 = [1,5,3,6,7], arr2 = [1,6,3,3]
<strong>Output:</strong> -1
<strong>Explanation:</strong> You can&#39;t make <code>arr1</code> strictly increasing.</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= arr1.length, arr2.length &lt;= 2000</code></li>
	<li><code>0 &lt;= arr1[i], arr2[i] &lt;= 10^9</code></li>
</ul>

<p>&nbsp;</p>

class Solution {
public:
    int dp[2001][2001][3];
    int f(int ind,int prev_ind,bool index_of_array,vector<int>&arr1,vector<int>&arr2){
        if(ind==arr1.size()) return 0;
        if(dp[ind][prev_ind][index_of_array]!=-1){
            return dp[ind][prev_ind][index_of_array];
        }
        int res_1=1e9+3;
        if(index_of_array && arr2[prev_ind]<arr1[ind]){
            res_1=f(ind+1,ind,0,arr1,arr2);
        }
        if(!index_of_array && arr1[prev_ind]<arr1[ind]){
            res_1=f(ind+1,ind,0,arr1,arr2);
        }
        int res_2=1e9+3;
        if(index_of_array){
            int pos=upper_bound(arr2.begin(),arr2.end(),arr2[prev_ind])-arr2.begin();
            if(pos<arr2.size())res_2=1+f(ind+1,pos,1,arr1,arr2);
        }
        else{
            int pos=upper_bound(arr2.begin(),arr2.end(),arr1[prev_ind])-arr2.begin();
            if(pos<arr2.size())res_2=1+f(ind+1,pos,1,arr1,arr2);
        }
        return dp[ind][prev_ind][index_of_array]= min(res_1,res_2);
    }
    int makeArrayIncreasing(vector<int>& arr1, vector<int>& arr2) {
        sort(arr2.begin(),arr2.end());
        if(arr1.size()==1) return 0;
        for(int i=0;i<2001;i++){
            for(int j=0;j<2001;j++){
                for(int k=0;k<3;k++){
                    dp[i][j][k]=-1;
                }
            }
        }
        int res_1=f(1,0,0,arr1,arr2);
        arr1[0]=arr2[0];
        int res_2=1+f(1,0,1,arr1,arr2);
        int res=min(res_1,res_2);
        return res>=1e9 ? -1 : res;
    }
};
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