<p>You are given two <strong>sorted</strong> arrays of distinct integers <code>nums1</code> and <code>nums2</code>.</p>

<p>A <strong>valid<strong><em> </em></strong>path</strong> is defined as follows:</p>

<ul>
	<li>Choose array <code>nums1</code> or <code>nums2</code> to traverse (from index-0).</li>
	<li>Traverse the current array from left to right.</li>
	<li>If you are reading any value that is present in <code>nums1</code> and <code>nums2</code> you are allowed to change your path to the other array. (Only one repeated value is considered in the valid path).</li>
</ul>

<p>The <strong>score</strong> is defined as the sum of unique values in a valid path.</p>

<p>Return <em>the maximum score you can obtain of all possible <strong>valid paths</strong></em>. Since the answer may be too large, return it modulo <code>10<sup>9</sup> + 7</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
<img alt="" src="https://assets.leetcode.com/uploads/2020/07/16/sample_1_1893.png" style="width: 500px; height: 151px;" />
<pre>
<strong>Input:</strong> nums1 = [2,4,5,8,10], nums2 = [4,6,8,9]
<strong>Output:</strong> 30
<strong>Explanation:</strong> Valid paths:
[2,4,5,8,10], [2,4,5,8,9], [2,4,6,8,9], [2,4,6,8,10],  (starting from nums1)
[4,6,8,9], [4,5,8,10], [4,5,8,9], [4,6,8,10]    (starting from nums2)
The maximum is obtained with the path in green <strong>[2,4,6,8,10]</strong>.
</pre>

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

<pre>
<strong>Input:</strong> nums1 = [1,3,5,7,9], nums2 = [3,5,100]
<strong>Output:</strong> 109
<strong>Explanation:</strong> Maximum sum is obtained with the path <strong>[1,3,5,100]</strong>.
</pre>

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

<pre>
<strong>Input:</strong> nums1 = [1,2,3,4,5], nums2 = [6,7,8,9,10]
<strong>Output:</strong> 40
<strong>Explanation:</strong> There are no common elements between nums1 and nums2.
Maximum sum is obtained with the path [6,7,8,9,10].
</pre>

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

<ul>
	<li><code>1 &lt;= nums1.length, nums2.length &lt;= 10<sup>5</sup></code></li>
	<li><code>1 &lt;= nums1[i], nums2[i] &lt;= 10<sup>7</sup></code></li>
	<li><code>nums1</code> and <code>nums2</code> are strictly increasing.</li>
</ul>

class Solution {
public:
    #define ll long long
    const int mod = 1e9+7 ;
    int maxSum(vector<int>& nums1, vector<int>& nums2) {
        unordered_map<int,int> a , b; 
        for(int i = 0 ; i < nums1.size() ; i++) 
            if(a.count(nums1[i]) == 0) a[nums1[i]] = i;
        for(int i = 0 ; i < nums2.size() ; i++) 
            if(b.count(nums2[i]) == 0) b[nums2[i]] = i;
        vector<int> idx1 , idx2;
        idx1.push_back(-1);
        idx2.push_back(-1);
        for(auto [k , f] : a){
            if(b.count (k)){
                idx1.push_back(f);
                idx2.push_back(b[k]);
            }              
        }

        idx1.push_back(nums1.size()-1);
        idx2.push_back(nums2.size()-1);
        sort(idx1.begin() , idx1.end());
        sort(idx2.begin() , idx2.end());

        ll ans = 0 ;

        auto sum = [](int l , int r,  vector<int>&nums){
            ll s = 0 ;
            for(int i = l ; i <= r; i++) s+=nums[i];
            return s;
        };

        for (int i = 0 ; i+1 < idx1.size() ; i++){
            ll sum1 = sum (idx1[i]+1 , idx1[i+1] , nums1);
            ll sum2 = sum (idx2[i]+1 , idx2[i+1] , nums2);
            ans += max (sum1 , sum2) ;
            ans %= mod;
        }
        return ans;
    }
};
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