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发表于 2008-12-9 14:41:09
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来自 陕西安康
Code 1
-
- In[1]:= ClearSystemCache[]
- Timing@(
- data1 = Range[100, 999];
- data2 =
- Union[Flatten[
- Table[data1[[i]] data1[[j]], {i, 1, 899}, {j, i + 1, 900}]]];
- Max@Select[data2, IntegerDigits[#] == Reverse[IntegerDigits[#]] &])
- Out[2]= {1.872, 906609}
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Code 2
-
- In[3]:= ClearSystemCache[]
- Timing@(data1 = Range[100, 999];
- data3 = {0, 0, 0};
- For[i = 1, i <= 899, i++,
- For[j = 2, j <= 900, j++, data = data1[[i]]*data1[[j]];
- If[IntegerDigits[data] == Reverse[IntegerDigits[data]] &&
- data > data3[[1]],
- data3 = {data, data1[[i]], data1[[j]]}
- ]
- ]
- ])
- data3
- Out[4]= {7.613, Null}
- Out[5]= {906609, 913, 993}
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Code 3
-
- In[7]:= Timing@(data1 = Range[100, 999];
- data2 =
- Sort[Select[
- Flatten[Table[{data1[[i]] data1[[j]], data1[[i]],
- data1[[j]]}, {i, 1, 899}, {j, i + 1, 900}], 1],
- IntegerDigits[#[[1]]] == Reverse@IntegerDigits[#[[1]]] &],
- #1[[1]] > #2[[1]] &];)
- data2[[1]]
- Out[7]= {3.323, Null}
- Out[8]= {906609, 913, 993}
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[ 本帖最后由 changqing 于 2008-12-9 15:06 编辑 ] |
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