Question 51 of 75 - LeetCode Weekly Challenge

LeetCode Challenge #2542. Maximum Subsequence Score

You are given two 0-indexed integer arrays nums1 and nums2 of equal length n and a positive integer k. You must choose a subsequence of indices from nums1 of length k.

For chosen indices i0i1, …, ik - 1, your score is defined as:

  • The sum of the selected elements from nums1 multiplied with the minimum of the selected elements from nums2.
  • It can defined simply as: (nums1[i0] + nums1[i1] +...+ nums1[ik - 1]) * min(nums2[i0] , nums2[i1], ... ,nums2[ik - 1]).

Return the maximum possible score.

subsequence of indices of an array is a set that can be derived from the set {0, 1, ..., n-1} by deleting some or no elements.

 

Example 1:

Input: nums1 = [1,3,3,2], nums2 = [2,1,3,4], k = 3
Output: 12
Explanation: 
The four possible subsequence scores are:
- We choose the indices 0, 1, and 2 with score = (1+3+3) * min(2,1,3) = 7.
- We choose the indices 0, 1, and 3 with score = (1+3+2) * min(2,1,4) = 6. 
- We choose the indices 0, 2, and 3 with score = (1+3+2) * min(2,3,4) = 12. 
- We choose the indices 1, 2, and 3 with score = (3+3+2) * min(1,3,4) = 8.
Therefore, we return the max score, which is 12.

Example 2:

Input: nums1 = [4,2,3,1,1], nums2 = [7,5,10,9,6], k = 1
Output: 30
Explanation: 
Choosing index 2 is optimal: nums1[2] * nums2[2] = 3 * 10 = 30 is the maximum possible score.

 

Constraints:

  • n == nums1.length == nums2.length
  • 1 <= n <= 105
  • 0 <= nums1[i], nums2[j] <= 105
  • 1 <= k <= n
Video Solution
C++ Solution
				
					class Solution {
public:
    long long maxScore(vector<int>& nums1, vector<int>& nums2, int k) {
        vector<pair<int,int>> pairs;

        int n=nums1.size();

        for(int i=0; i<n; i++)
        {
            pairs.push_back({nums2[i],nums1[i]});
        }
        sort(pairs.begin(),pairs.end());
        reverse(pairs.begin(),pairs.end());

        priority_queue<int,vector<int>,greater<int>> pq;

        long long sum=0;
        long long ans=0;

        for(int i=0; i<n; i++)
        {
            pq.push(pairs[i].second);
            sum+=pairs[i].second;

            if(pq.size()>k)
            {
                sum-=pq.top();
                pq.pop();
            }

            if(pq.size()==k) ans= max(ans,(long long)sum*pairs[i].first);
        }

        return ans;

    }
};
				
			

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