SRM620 Div1 Easy in C++ PairGame

PairGame.cpp

#include <cstdio>
#include <cmath>
#include <cstring>
#include <ctime>
#include <iostream>
#include <algorithm>
#include <set>
#include <vector>
#include <map>
#include <tuple>
#include <sstream>
#include <typeinfo>
#include <fstream>

using namespace std;

class PairGame {
    public:
    vector<vector<int> > parts(int a, int b){
    	vector<vector<int> > sums(2000000);
  
    	sums[a+b] = {a,b};
    	while(a > 0 and b > 0){
    		if (a > b) {
    			a = a - b;
    		} else {
    			b = b - a;
    		}
    		sums[a+b] = {a,b};
    	}
    	return sums;
    }

    int maxSum(int a, int b, int c, int d) {
    	auto sumsA = parts(a, b);
    	auto sumsC = parts(c, d);

    	for (int i = sumsA.size() - 1; i >= 0; --i){
    		if (!sumsC[i].empty()){
    			if (sumsA[i] == sumsC[i]){
    				return i;
    			}
    		}
    	}
        return -1;
    }

};