Cod sursa(job #906561)

Utilizator sebii_cSebastian Claici sebii_c Data 6 martie 2013 21:50:56
Problema Semne Scor 5
Compilator cpp Status done
Runda Arhiva de probleme Marime 0.83 kb
#include <cstdio>
#include <cstdlib>
#include <ctime>

const int MAXN = 50001;

int S, N;
long long A[MAXN];

bool mark[MAXN];
char res[MAXN];

bool doit(long long sum, int pos)
{
    if (sum < S)
        return false;
    if (sum == S)
        return true;

    while (true) {
        int i = rand() % (pos + 1);
        res[i] = '-';
        if (doit(sum - 2 * A[i], i - 1))
            return true;
        res[i] = '+';
    }

    return false;
}

int main()
{
    freopen("semne.in", "r", stdin);
    freopen("semne.out", "w", stdout);
    srand(time(NULL));

    scanf("%d %d", &N, &S);

    long long sum = 0;
    for (int i = 0; i < N; ++i) {
        scanf("%lld", &A[i]);
        sum += A[i];
        res[i] = '+';
    }

    doit(sum, N - 1);
    for (int i = 0; i < N; ++i)
        printf("%c", res[i]);
    printf("\n");

    return 0;
}