Find Positive Integer Solution for a Given Equation Solutions in C++

/// Source : https://leetcode.com/problems/find-positive-integer-solution-for-a-given-equation/
/// Author : liuyubobobo
/// Time   : 2019-10-26

#include <iostream>
#include <vector>

using namespace std;


/// Brute Force
/// Time Complexity: O(1000 * 1000)
/// Space Complexity: O(1)
class Solution {
public:
    vector<vector<int>> findSolution(CustomFunction& customfunction, int z) {

        vector<vector<int>> res;
        for(int x = 1; x <= 1000; x ++)
            for(int y = 1; y <= 1000; y ++)
                if(customfunction.f(x, y) == z) res.push_back({x, y});
        return res;
    }
};


int main() {

    return 0;
}

/// Source : https://leetcode.com/problems/find-positive-integer-solution-for-a-given-equation/
/// Author : liuyubobobo
/// Time   : 2019-11-01

#include <iostream>
#include <vector>

using namespace std;


/// Binary Search
/// Time Complexity: O(1000 * log(1000))
/// Space Complexity: O(1)
class Solution {
public:
    vector<vector<int>> findSolution(CustomFunction& customfunction, int z) {

        vector<vector<int>> res;
        for(int x = 1; x <= z; x ++){
            int l = 1, r = 1000;
            while(l <= r){
                int mid = (l + r) / 2;
                int v = customfunction.f(x, mid);
                if(v == z){
                    res.push_back({x, mid});
                    break;
                }
                else if(v < z) l = mid + 1;
                else r = mid - 1;
            }
        }
        return res;
    }
};


int main() {

    return 0;
}

/// Source : https://leetcode.com/problems/find-positive-integer-solution-for-a-given-equation/
/// Author : liuyubobobo
/// Time   : 2019-11-03

#include <iostream>
#include <vector>

using namespace std;


/// Two Pointers
/// Time Complexity: O(1000)
/// Space Complexity: O(1)
class Solution {
public:
    vector<vector<int>> findSolution(CustomFunction& customfunction, int z) {

        vector<vector<int>> res;
        for(int x = 1, y = 1000; x <= 1000 && y >= 1;){
            int v = customfunction.f(x, y);
            if(v == z) res.push_back({x ++, y --};
            else if(v < z) y --;
            else x ++;
        }
        return res;
    }
};


int main() {

    return 0;
}