Submission #5924914

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

typedef pair<int, int> pii;

int n, num;
vector<int> a, b, c;
vector<pii> vec;

int main() {
	ios::sync_with_stdio(false), cin.tie(0);
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> num;
		if(num < 0)
			a.push_back(num);
		else if(num == 0)
			c.push_back(num);
		else
			b.push_back(num);
	}
	sort(a.begin(), a.end());
	sort(b.begin(), b.end(), greater<int>());
	if(a.empty() && b.empty()) {
		cout << "0\n";
		for (int i = 0; i < n - 1; i++)
			cout << 0 << ' ' << 0 << '\n';
		return 0;
	}
	if(a.empty()) {
		if(c.size())
			a = c;
		else {
			a.push_back(b.back());
			b.pop_back();
		}
	}
	else if(b.empty()) {
		if(c.size())
			b = c;
		else {
			b.push_back(a.back());
			a.pop_back();
		}
	}
	else {
		for (int num: c)
			a.push_back(num);
	}
	
	for (int i = 0; i < n - 1; i++) {
		if(a.size() < b.size()) {
			vec.push_back(pii(a.back(), b.back()));
			int num = a.back() - b.back();
			a.pop_back(), b.pop_back();
			a.push_back(num);
		}
		else {
			vec.push_back(pii(b.back(), a.back()));
			int num = b.back() - a.back();
			a.pop_back(), b.pop_back();
			b.push_back(num);
		}
	}
	cout << b.back() << '\n';
	for (pii p: vec)
		cout << p.first << ' ' << p.second << '\n';
	return 0;
}

Submission Info

Judge Result