<p>You are given two integer arrays of the same length <code>nums1</code> and <code>nums2</code>. In one operation, you are allowed to swap <code>nums1[i]</code> with <code>nums2[i]</code>.</p>

<ul>
	<li>For example, if <code>nums1 = [1,2,3,<u>8</u>]</code>, and <code>nums2 = [5,6,7,<u>4</u>]</code>, you can swap the element at <code>i = 3</code> to obtain <code>nums1 = [1,2,3,4]</code> and <code>nums2 = [5,6,7,8]</code>.</li>
</ul>

<p>Return <em>the minimum number of needed operations to make </em><code>nums1</code><em> and </em><code>nums2</code><em> <strong>strictly increasing</strong></em>. The test cases are generated so that the given input always makes it possible.</p>

<p>An array <code>arr</code> is <strong>strictly increasing</strong> if and only if <code>arr[0] &lt; arr[1] &lt; arr[2] &lt; ... &lt; arr[arr.length - 1]</code>.</p>

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

<pre>
<strong>Input:</strong> nums1 = [1,3,5,4], nums2 = [1,2,3,7]
<strong>Output:</strong> 1
<strong>Explanation:</strong> 
Swap nums1[3] and nums2[3]. Then the sequences are:
nums1 = [1, 3, 5, 7] and nums2 = [1, 2, 3, 4]
which are both strictly increasing.
</pre>

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

<pre>
<strong>Input:</strong> nums1 = [0,3,5,8,9], nums2 = [2,1,4,6,9]
<strong>Output:</strong> 1
</pre>

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

<ul>
	<li><code>2 &lt;= nums1.length &lt;= 10<sup>5</sup></code></li>
	<li><code>nums2.length == nums1.length</code></li>
	<li><code>0 &lt;= nums1[i], nums2[i] &lt;= 2 * 10<sup>5</sup></code></li>
</ul>

class Solution {
public:
    // int solve(int i,vector<int>& nums1, vector<int>& nums2,int n,vector<array<int,2>> &dp){
    //     if(i==n)return 0;
    //     int ans=INT_MAX;
    //     if(dp[i][1]==2) return dp[i][0];
    //     if(i==0 || (nums1[i]>nums1[i-1] && nums2[i]>nums2[i-1])){
    //         ans=solve(i+1,nums1,nums2,n,dp);
    //     }
    //     if( i>0 && nums1[i]>nums2[i-1] && nums2[i]>nums1[i-1]){
    //         swap(nums1[i],nums2[i]);
    //         ans=min(ans,1+solve(i+1,nums1,nums2,n,dp));
    //         swap(nums1[i],nums2[i]);
    //     }
    //     // cout<<i<<" "<<ans<<endl;
    //     dp[i][1]++;
    //     return dp[i][0]=ans;
    // }
    int minSwap(vector<int>& a, vector<int>& b) {
        int n=a.size();
        int dp[100000][2]={};
        dp[n-1][0]=0;
        dp[n-1][1]=1;
        for(int i=n-2;i>=0;i--){
            for(int j=0;j<2;j++){
                dp[i][j]=1000000000;
                if(j==0){
                    if(a[i+1]>a[i] && b[i+1]>b[i])dp[i][j]=dp[i+1][j];
                    if(b[i+1]>a[i] && a[i+1]>b[i])dp[i][j]=min(dp[i][j],dp[i+1][1]);
                }
                else{
                    if(a[i+1]>a[i] && b[i+1]>b[i])dp[i][j]=dp[i+1][j]+1;
                    if(b[i+1]>a[i] && a[i+1]>b[i])dp[i][j]=min(dp[i][j],1+dp[i+1][0]);
                }
            }
        }
        return min(dp[0][0],dp[0][1]);
    }
};
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