Solution in C++ :

int solve(vector<vector<int>>& reviews, int threshold) {
    double fi = 0, xi = 0;
    for (int i = 0; i < reviews.size(); i++) {
        fi += reviews[i][1];
        xi += reviews[i][0];
    }

    return max((double)0,
               ceil((threshold * fi - 100 * xi) / max((double)1, (100 - (double)threshold))));
}
                    

                        Solution in Java :

import java.util.*;

class Solution {
    public int solve(int[][] reviews, int threshold) {
        if (threshold == 0)
            return 0;
        int totalReview = 0;
        int total5Star = 0;
        for (int i = 0; i < reviews.length; i++) {
            totalReview += reviews[i][1];
            total5Star += reviews[i][0];
        }

        // (totalReview + x) * threshold / 100 = (total5Star + x)

        int res = (int) Math.ceil(
            (double) ((totalReview * threshold) - (100 * total5Star)) / (100 - threshold));

        return res;
    }
}
                    

                        Solution in Python : 
                            
class Solution:
    def solve(self, reviews, threshold):
        a = 0
        b = 0
        for c, d in reviews:
            a += c
            b += d
        if a * 100 >= threshold * b:
            return 0
        delta = threshold * b - 100 * a
        return (delta + (99 - threshold)) // (100 - threshold)