Advantage Shuffle

Description

Given two arrays A and B of equal size, the advantage of A with respect to B is the number of indices i for which A[i] > B[i].

Return any permutation of A that maximizes its advantage with respect to B.

Example 1:

Input: A = [2,7,11,15], B = [1,10,4,11]
Output: [2,11,7,15]

Example 2:

Input: A = [12,24,8,32], B = [13,25,32,11]
Output: [24,32,8,12]

Note:

1. 1 <= A.length = B.length <= 10000

2. 0 <= A[i] <= 10^9

3. 0 <= B[i] <= 10^9

Solution

class Solution {
public:
    vector<int> advantageCount(vector<int>& A, vector<int>& B) {
        int n = A.size();
        vector<int> ans(n, -1);
        multiset<int> nums(A.begin(), A.end());
        for(int i = 0; i < n; ++i){
            auto it = nums.upper_bound(B[i]);
            if(it != nums.end()){
                ans[i] = *it;
                nums.erase(it);
            }
        }
        auto it = nums.begin();
        for(int i = 0; i < n; ++i){
            if(ans[i] < 0){
                ans[i] = *it;
                ++it;
            }
        }
        return ans;
    }
};