codeforces 199a

link:http://codeforces.com/contest/342/problem/A

恩恩，读错题了。人家是at most 7，我理解成了at lease 7。好欢乐~

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>
using namespace std;
int cnt[8];
int main(void) {
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
#endif
    int n, i, j, tmp;
    bool flag;
    while (~scanf("%d", &n))  {
        flag = true;
        memset(cnt, 0, sizeof(cnt));
        for (i = 0; i < n; ++i) {
            scanf("%d", &tmp);
            cnt[tmp]++;
        }
        int sum = cnt[5] + cnt[7];
        if (sum > 0) {
            printf("-1\n"); continue;
        }
        int c136 = 0, c126 = 0, c124 = 0;
        if (cnt[1] >= cnt[3] && cnt[6] >= cnt[3])
        {cnt[1] -= cnt[3]; cnt[6] -= cnt[3]; c136 = cnt[3];}
        else flag = false;
        if (cnt[1] >= cnt[6] && cnt[2] >= cnt[6])
        {cnt[1] -= cnt[6]; cnt[2] -= cnt[6]; c126 = cnt[6];}
        else flag = false;
        if (cnt[1] >= cnt[4] && cnt[2] >= cnt[4]) {
        c124 = cnt[4]; cnt[1] -= cnt[4]; cnt[2] -= cnt[4];}
        else flag = false;
        if (cnt[1]+cnt[2] > 0) flag = false;
        if (flag) {
            for (i = 0; i < c136; ++i) printf("1 3 6\n");
            for (j = 0; j < c126; ++j) printf("1 2 6\n");
            for (i = 0; i < c124; ++i) printf("1 2 4\n");
        }
        else printf("-1\n");
    }
    return 0;
}

闲的没事儿干，没事儿做做题=_=

嗨，中村。