习题8-10(uva-1614)

#include <iostream>
#include <istream>
#include <sstream>
#include <vector>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <numeric>
#include <chrono>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <cstdio>
#include <iomanip>


#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <iterator>
using namespace std;
const int maxn = 1e6 + 7;
int input[maxn], n;
char sign[maxn];

bool dfs(long long int cur, long long int s) {
	if (s == 0) return true;
	if (s < 0 || cur <= 0 ) return false;
	cur = min(cur, s);
	for (int i = cur; i >= 1; i--) {
		if (input[i] > s) return false;
		sign[i] = 1;
		if (dfs(i - 1, s - input[i])) return true;
		sign[i] = 0;
	}
	return false;
}
int main()
{
	while (cin >> n) {
		memset(sign, 0, sizeof(sign));
		long long int sum = 0,dir = 0;
		for (int i = 1; i <= n; i++) {
			cin >> input[i];
			sum += input[i];
		}
		dir = sum >> 1;
		if ((sum & 1) || (input[n] > dir)) {
			cout << "No" << endl;
		}
		else {
			if (dfs(n, dir)) {
				cout << "Yes" << endl;
				cout << (sign[1] ? "+1" : "-1");
				for (int i = 2; i <= n; i++) {
					cout <<" "<< (sign[i] ? "+1" : "-1");
				}
				cout << endl;
			}else
				cout << "No" << endl;
		}
	}
	return 0;
}