通过运行【5，100000000】之内的回文素数，发现规律：
5 100000000
回文素数没有4、6、8位的，虽然数的范围是到100,000,000，但是最后一个数只到9989899为止（七位数）。所以直接加一个
if(i>=10000000) return 0;
就可以AC了。
火柴棒
24
0(6) + 8(7) = 8(7)总共20根火柴
0(6) + 12(7) = 12(7)总共20根火柴
0(6) + 13(7) = 13(7)总共20根火柴
0(6) + 15(7) = 15(7)总共20根火柴
0(6) + 21(7) = 21(7)总共20根火柴
0(6) + 31(7) = 31(7)总共20根火柴
0(6) + 47(7) = 47(7)总共20根火柴
0(6) + 51(7) = 51(7)总共20根火柴
0(6) + 74(7) = 74(7)总共20根火柴
0(6) + 117(7) = 117(7)总共20根火柴
0(6) + 171(7) = 171(7)总共20根火柴
0(6) + 711(7) = 711(7)总共20根火柴
1(2) + 20(11) = 21(7)总共20根火柴
1(2) + 30(11) = 31(7)总共20根火柴
1(2) + 42(9) = 43(9)总共20根火柴
1(2) + 47(7) = 48(11)总共20根火柴
1(2) + 50(11) = 51(7)总共20根火柴
1(2) + 112(9) = 113(9)总共20根火柴
1(2) + 117(7) = 118(11)总共20根火柴
1(2) + 170(11) = 171(7)总共20根火柴
1(2) + 710(11) = 711(7)总共20根火柴
2(5) + 8(7) = 10(8)总共20根火柴
2(5) + 10(8) = 12(7)总共20根火柴
2(5) + 19(8) = 21(7)总共20根火柴
2(5) + 41(6) = 43(9)总共20根火柴
2(5) + 72(8) = 74(7)总共20根火柴
2(5) + 77(6) = 79(9)总共20根火柴
2(5) + 111(6) = 113(9)总共20根火柴
3(5) + 10(8) = 13(7)总共20根火柴
3(5) + 13(7) = 16(8)总共20根火柴
3(5) + 44(8) = 47(7)总共20根火柴
3(5) + 114(8) = 117(7)总共20根火柴
4(4) + 43(9) = 47(7)总共20根火柴
4(4) + 57(8) = 61(8)总共20根火柴
4(4) + 70(9) = 74(7)总共20根火柴
4(4) + 113(9) = 117(7)总共20根火柴
4(4) + 117(7) = 121(9)总共20根火柴
5(5) + 10(8) = 15(7)总共20根火柴
5(5) + 16(8) = 21(7)总共20根火柴
5(5) + 17(5) = 22(10)总共20根火柴
6(6) + 15(7) = 21(7)总共20根火柴
7(3) + 15(7) = 22(10)总共20根火柴
7(3) + 27(8) = 34(9)总共20根火柴
7(3) + 40(10) = 47(7)总共20根火柴
7(3) + 41(6) = 48(11)总共20根火柴
7(3) + 54(9) = 61(8)总共20根火柴
7(3) + 72(8) = 79(9)总共20根火柴
7(3) + 77(6) = 84(11)总共20根火柴
7(3) + 110(10) = 117(7)总共20根火柴
7(3) + 111(6) = 118(11)总共20根火柴
7(3) + 114(8) = 121(9)总共20根火柴
8(7) + 0(6) = 8(7)总共20根火柴
8(7) + 2(5) = 10(8)总共20根火柴
9(6) + 12(7) = 21(7)总共20根火柴
10(8) + 2(5) = 12(7)总共20根火柴
10(8) + 3(5) = 13(7)总共20根火柴
10(8) + 5(5) = 15(7)总共20根火柴
11(4) + 13(7) = 24(9)总共20根火柴
11(4) + 14(6) = 25(10)总共20根火柴
11(4) + 16(8) = 27(8)总共20根火柴
11(4) + 31(7) = 42(9)总共20根火柴
11(4) + 41(6) = 52(10)总共20根火柴
11(4) + 61(8) = 72(8)总共20根火柴
12(7) + 0(6) = 12(7)总共20根火柴
12(7) + 9(6) = 21(7)总共20根火柴
13(7) + 0(6) = 13(7)总共20根火柴
13(7) + 3(5) = 16(8)总共20根火柴
13(7) + 11(4) = 24(9)总共20根火柴
14(6) + 11(4) = 25(10)总共20根火柴
14(6) + 27(8) = 41(6)总共20根火柴
14(6) + 77(6) = 91(8)总共20根火柴
15(7) + 0(6) = 15(7)总共20根火柴
15(7) + 6(6) = 21(7)总共20根火柴
15(7) + 7(3) = 22(10)总共20根火柴
16(8) + 5(5) = 21(7)总共20根火柴
16(8) + 11(4) = 27(8)总共20根火柴
17(5) + 5(5) = 22(10)总共20根火柴
17(5) + 24(9) = 41(6)总共20根火柴
17(5) + 57(8) = 74(7)总共20根火柴
17(5) + 74(7) = 91(8)总共20根火柴
19(8) + 2(5) = 21(7)总共20根火柴
20(11) + 1(2) = 21(7)总共20根火柴
21(7) + 0(6) = 21(7)总共20根火柴
24(9) + 17(5) = 41(6)总共20根火柴
27(8) + 7(3) = 34(9)总共20根火柴
27(8) + 14(6) = 41(6)总共20根火柴
30(11) + 1(2) = 31(7)总共20根火柴
31(7) + 0(6) = 31(7)总共20根火柴
31(7) + 11(4) = 42(9)总共20根火柴
40(10) + 7(3) = 47(7)总共20根火柴
41(6) + 2(5) = 43(9)总共20根火柴
41(6) + 7(3) = 48(11)总共20根火柴
41(6) + 11(4) = 52(10)总共20根火柴
41(6) + 71(5) = 112(9)总共20根火柴
42(9) + 1(2) = 43(9)总共20根火柴
43(9) + 4(4) = 47(7)总共20根火柴
44(8) + 3(5) = 47(7)总共20根火柴
47(7) + 0(6) = 47(7)总共20根火柴
47(7) + 1(2) = 48(11)总共20根火柴
50(11) + 1(2) = 51(7)总共20根火柴
51(7) + 0(6) = 51(7)总共20根火柴
54(9) + 7(3) = 61(8)总共20根火柴
57(8) + 4(4) = 61(8)总共20根火柴
57(8) + 17(5) = 74(7)总共20根火柴
61(8) + 11(4) = 72(8)总共20根火柴
70(9) + 4(4) = 74(7)总共20根火柴
71(5) + 41(6) = 112(9)总共20根火柴
72(8) + 2(5) = 74(7)总共20根火柴
72(8) + 7(3) = 79(9)总共20根火柴
74(7) + 0(6) = 74(7)总共20根火柴
74(7) + 17(5) = 91(8)总共20根火柴
77(6) + 2(5) = 79(9)总共20根火柴
77(6) + 7(3) = 84(11)总共20根火柴
77(6) + 14(6) = 91(8)总共20根火柴
110(10) + 7(3) = 117(7)总共20根火柴
111(6) + 2(5) = 113(9)总共20根火柴
111(6) + 7(3) = 118(11)总共20根火柴
112(9) + 1(2) = 113(9)总共20根火柴
113(9) + 4(4) = 117(7)总共20根火柴
114(8) + 3(5) = 117(7)总共20根火柴
114(8) + 7(3) = 121(9)总共20根火柴
117(7) + 0(6) = 117(7)总共20根火柴
117(7) + 1(2) = 118(11)总共20根火柴
117(7) + 4(4) = 121(9)总共20根火柴
170(11) + 1(2) = 171(7)总共20根火柴
171(7) + 0(6) = 171(7)总共20根火柴
710(11) + 1(2) = 711(7)总共20根火柴
711(7) + 0(6) = 711(7)总共20根火柴
128
Program ended with exit code: 0
三连击升级版：
要特判一个特例123 456 789.