uva-10344

题意：

枚举23点,注意,数字也是可以枚举的，wa了一次

#include<stdio.h>
#include<iostream>
#include<sstream>
#include<queue>
#include<map>
#include<memory.h>
#include <math.h>
#include<time.h>
#include <stdlib.h>
#include <algorithm>
using namespace std;
#define N 12
int vis[N];
int a[N];
int b[N];
int n;
int final = 0;

void dfs(int cur, int total)
{
    if(cur == 5 && total == 23)
    {
        final = 1;
        return;
    }
    for(int i = 0; i < 5 && !final; i++)
    {
        if(vis[i])
            continue;

        vis[i] = 1;
        if(cur != 0)
        {
            dfs(cur + 1, total - a[i]);
            dfs(cur + 1, total + a[i]);
            dfs(cur + 1, total * a[i]);
        }
        else
        {
            dfs(cur + 1, a[i]);
        }
        vis[i] = 0;
    }

}
int main(const int argc, char** argv)
{
    freopen("d:\\1.txt", "r", stdin);
    while (scanf("%d %d %d %d %d", a, a + 1, a + 2, a + 3, a + 4))
    {
        if(a[0] || a[1] || a[3] || a[4])
        {
            final = 0;
            memset(vis, 0, sizeof(vis));
            dfs(0, 0);
            if(final)
                cout << "Possible" << endl;
            else
                cout << "Impossible" << endl;

        }
        else
        {
            return 0;
        }
    }
    return 0;
}