<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 dp[100001][2];
    vector<int> a, b;
    int n, OO = 200003;
    int getMinFromI(int i, bool isLastSwapped, int lastA, int lastB) {
        if (i == n)
            return 0;
        if(dp[i][isLastSwapped] != -1)
            return dp[i][isLastSwapped];
        int swap = OO, noSwap = OO;
        if(!(a[i] <= lastB || b[i] <= lastA))
            swap = 1 + getMinFromI(i + 1, true, b[i], a[i]);
            
        if(a[i] > lastA && b[i] > lastB)
            noSwap = getMinFromI(i + 1, false, a[i], b[i]);
        return dp[i][isLastSwapped] = min(swap, noSwap);
    }
    int minSwap(vector<int>& nums1, vector<int>& nums2) {
        n = nums1.size();
        memset(dp, -1, sizeof(dp));
        a = nums1, b = nums2;
        int ans = getMinFromI(0, false, -1, -1);
        for (int i = 0; i < n; ++i)
            cout << i << " ";
        cout << endl;
        for (int i = 0; i < 2; ++i) {
            for (int j = 0; j < n; ++j)
                cout << dp[j][i] << " ";
            cout << endl;
        }
        return ans;
    }
};

/*
[0,4,5,7, 10,11,12,13,19,18]
[4,7,8,10,11,14,15,16,17,20]
*/
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