1234,1235,1236,1237,1238,1245,1246,1247,1248,1256,1257,1258,1267,1268,1278,
1345,1346,1347,1348,1356,1357,1358,1367,1368,1378
1456,1457,1458,1467,1468,1478
1567,1568,1578
1678
35个
2345,2346,2347,2348,2356,2357,2358,2367,2368,2378
2456,2457,2458,2467,2468,2478
2567,2568,2578
2678
20个
3456,3457,3458,3467,3468,3478
3567,3568,3578
3678
10个
4567,4568,4578
4678
4个
5678
1个
共C8(4)=70个………………
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