【POJ】2718 - Smallest Difference（枚举全排列）

#include<cstdio>
#include<algorithm>
#include<iostream>
using namespace std;
int main()
{
    int u;
    int num[15];
    char ch;
    int n,half;
    scanf ("%d",&u);
    int ans;
    while (u--)
    {
        n = 0;
        ans = 0x3f3f3f3f;
        while (scanf ("%d%c",&num[++n],&ch) && ch != '\n');
        if (n == 10)
        {
            cout << 247 << endl;
            continue;
        }
        else if (n == 2)
        {
            cout << num[2] - num[1] << endl;
            continue;
        }
        int a,b;
        half = n >> 1;
        do
        {
            if (num[1] == 0 || num[half+1] == 0)
                continue;
            int pos = 1;
            a = b = 0;
            for ( ; pos <= half ; pos++)
                a = a*10 + num[pos];
            for ( ; pos <= n ; pos++)
                b = b*10 + num[pos];
            ans = min(ans , abs(a-b));
//          if (abs(a-b) < ans)
//          {
//              ans = abs(a-b);
//              cout << "===" << a << ' ' << b << "===" << endl; 
//          }
        }while (next_permutation(num+1,num+1+n));
        cout << ans << endl;
    }
    return 0;
}