Twenty-fourpoint

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#include <iostream>#include <algorithm>#include <queue>#include <cstring>#include <cstdio>#include <vector>#include <string>#include <iterator>#include <cmath>#include <deque>#include <stack>#include <cctype>#include <iomanip>using namespace std;typedef long long ll;typedef long double ld;const int N = 1100;const int INF = 0xfffffff;const double EPS = 1e-8;const ll MOD = 1e9 + 7;const ld PI = acos (-1.0);#define INFL 0x7fffffffffffffffLL#define met(a, b) memset(a, b, sizeof(a))#define put(a) cout << setiosflags(ios::fixed) << setprecision(a)double a[5];bool dfs (double *a, int n);int main (){    while (cin >> a[0] >> a[1] >> a[2] >> a[3])    {        if (dfs (a, 4))            puts("Yes");        else            puts("No");    }    return 0;}bool dfs (double *a, int n){    double tmp[5];    if (n == 1) return fabs(a[0] - 24 ) < EPS;    for (int i=0; i<n; i++)    {        for (int j=i; j<n; j++)        {            if (i == j) continue;            int len = 0;            for (int k=0; k<n; k++)            {                if (k != i && k != j)                    tmp[len++] = a[k];            }            tmp[len] = a[i] + a[j];            if (dfs(tmp, n - 1)) return true;            tmp[len] = a[i] - a[j];            if (dfs (tmp, n - 1)) return true;            tmp[len] = a[j] - a[i];            if (dfs (tmp, n - 1)) return true;            tmp[len] = a[i] * a[j];            if (dfs (tmp, n - 1)) return true;            if (a[i] != 0)            {                tmp[len] = a[j] / a[i];                if (dfs (tmp, n - 1)) return true;            }            if (a[j] != 0)            {                tmp[len] = a[i] / a[j];                if (dfs(tmp, n - 1)) return true;            }        }    }    return false;}
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