2248. Intersection of Multiple Arrays

Given a 2D integer array nums where nums[i] is a non-empty array of distinct positive integers, return the list of integers that are present in each array of nums sorted in ascending order.

#define all(a) begin(a), end(a)
using namespace std;

class Solution {
    pair<bool, int> eq(vector<vector<int>>& nums, vector<int>& pos) {
        int target = nums[0][pos[0]];
        for(int i = 0; i < pos.size(); i++)
            if(target != nums[i][pos[i]]) {
                return {false, i};
            }
        return {true, -1};
    }
public:
    vector<int> intersection(vector<vector<int>>& nums) {
        vector<int> res;
        int n = nums.size();
        vector<int> pos(n, 0);
        for(auto& n : nums)
            sort(all(n));
        bool eof = false;
        while(!eof) {
            auto [pb, po] = eq(nums,pos);
            if(pb) {
                res.push_back(nums[0][pos[0]]);
                for(int i = 0; i < pos.size(); i++) {
                    if(++pos[i] == nums[i].size()) eof = true;
                }
            } else {
                int req = max(nums[0][pos[0]], nums[po][pos[po]]);
                for(int i = 0; i < pos.size(); i++) {
                    while(!eof and nums[i][pos[i]] < req) {
                        if(++pos[i] == nums[i].size())
                            eof = true;
                    }
                }
            }
        }
        return res;
    }
};