1 #include <iostream> 2 #include <cstdio> 3 #include <cstdlib> 4 #include <cmath> 5 #define sc(x,y) scanf("%d %d",&(x),&(y)) 6 #define pf(x) printf("%d ", x) 7 using namespace std; 8 int a, b; 9 int arr[]= {2,3,5,7,11,101,131,151,181,191,313,353,373,383,727,757,787,797,919,929, 10 10301,10501,10601,11311,11411,12421,12721,12821,13331,13831,13931,14341,14741,15451,15551, 11 16061,16361,16561,16661,17471,17971,18181,18481,19391,19891,19991,30103,30203,30403,30703, 12 30803,31013,31513,32323,32423,33533,34543,34843,35053,35153,35353,35753,36263,36563,37273, 13 37573,38083,38183,38783,39293,70207,70507,70607,71317,71917,72227,72727,73037,73237,73637, 14 74047,74747,75557,76367,76667,77377,77477,77977,78487,78787,78887,79397,79697,79997,90709, 15 91019,93139,93239,93739,94049,94349,94649,94849,94949,95959,96269,96469,96769,97379,97579, 16 97879,98389,98689,1003001,1008001,1022201,1028201,1035301,1043401,1055501,1062601,1065601, 17 1074701,1082801,1085801,1092901,1093901,1114111,1117111,1120211,1123211,1126211,1129211,1134311, 18 1145411,1150511,1153511,1160611,1163611,1175711,1177711,1178711,1180811,1183811,1186811,1190911, 19 1193911,1196911,1201021,1208021,1212121,1215121,1218121,1221221,1235321,1242421,1243421,1245421, 20 1250521,1253521,1257521,1262621,1268621,1273721,1276721,1278721,1280821,1281821,1286821,1287821, 21 1300031,1303031,1311131,1317131,1327231,1328231,1333331,1335331,1338331,1343431,1360631,1362631, 22 1363631,1371731,1374731,1390931,1407041,1409041,1411141,1412141,1422241,1437341,1444441,1447441, 23 1452541,1456541,1461641,1463641,1464641,1469641,1486841,1489841,1490941,1496941,1508051,1513151, 24 1520251,1532351,1535351,1542451,1548451,1550551,1551551,1556551,1557551,1565651,1572751,1579751, 25 1580851,1583851,1589851,1594951,1597951,1598951,1600061,1609061,1611161,1616161,1628261,1630361, 26 1633361,1640461,1643461,1646461,1654561,1657561,1658561,1660661,1670761,1684861,1685861,1688861, 27 1695961,1703071,1707071,1712171,1714171,1730371,1734371,1737371,1748471,1755571,1761671,1764671, 28 1777771,1793971,1802081,1805081,1820281,1823281,1824281,1826281,1829281,1831381,1832381,1842481, 29 1851581,1853581,1856581,1865681,1876781,1878781,1879781,1880881,1881881,1883881,1884881,1895981, 30 1903091,1908091,1909091,1917191,1924291,1930391,1936391,1941491,1951591,1952591,1957591,1958591, 31 1963691,1968691,1969691,1970791,1976791,1981891,1982891,1984891,1987891,1988891,1993991,1995991, 32 1998991,3001003,3002003,3007003,3016103,3026203,3064603,3065603,3072703,3073703,3075703,3083803, 33 3089803,3091903,3095903,3103013,3106013,3127213,3135313,3140413,3155513,3158513,3160613,3166613, 34 3181813,3187813,3193913,3196913,3198913,3211123,3212123,3218123,3222223,3223223,3228223,3233323, 35 3236323,3241423,3245423,3252523,3256523,3258523,3260623,3267623,3272723,3283823,3285823,3286823, 36 3288823,3291923,3293923,3304033,3305033,3307033,3310133,3315133,3319133,3321233,3329233,3331333, 37 3337333,3343433,3353533,3362633,3364633,3365633,3368633,3380833,3391933,3392933,3400043,3411143, 38 3417143,3424243,3425243,3427243,3439343,3441443,3443443,3444443,3447443,3449443,3452543,3460643, 39 3466643,3470743,3479743,3485843,3487843,3503053,3515153,3517153,3528253,3541453,3553553,3558553, 40 3563653,3569653,3586853,3589853,3590953,3591953,3594953,3601063,3607063,3618163,3621263,3627263, 41 3635363,3643463,3646463,3670763,3673763,3680863,3689863,3698963,3708073,3709073,3716173,3717173, 42 3721273,3722273,3728273,3732373,3743473,3746473,3762673,3763673,3765673,3768673,3769673,3773773, 43 3774773,3781873,3784873,3792973,3793973,3799973,3804083,3806083,3812183,3814183,3826283,3829283, 44 3836383,3842483,3853583,3858583,3863683,3864683,3867683,3869683,3871783,3878783,3893983,3899983, 45 3913193,3916193,3918193,3924293,3927293,3931393,3938393,3942493,3946493,3948493,3964693,3970793, 46 3983893,3991993,3994993,3997993,3998993,7014107,7035307,7036307,7041407,7046407,7057507,7065607, 47 7069607,7073707,7079707,7082807,7084807,7087807,7093907,7096907,7100017,7114117,7115117,7118117, 48 7129217,7134317,7136317,7141417,7145417,7155517,7156517,7158517,7159517,7177717,7190917,7194917, 49 7215127,7226227,7246427,7249427,7250527,7256527,7257527,7261627,7267627,7276727,7278727,7291927, 50 7300037,7302037,7310137,7314137,7324237,7327237,7347437,7352537,7354537,7362637,7365637,7381837, 51 7388837,7392937,7401047,7403047,7409047,7415147,7434347,7436347,7439347,7452547,7461647,7466647, 52 7472747,7475747,7485847,7486847,7489847,7493947,7507057,7508057,7518157,7519157,7521257,7527257, 53 7540457,7562657,7564657,7576757,7586857,7592957,7594957,7600067,7611167,7619167,7622267,7630367, 54 7632367,7644467,7654567,7662667,7665667,7666667,7668667,7669667,7674767,7681867,7690967,7693967, 55 7696967,7715177,7718177,7722277,7729277,7733377,7742477,7747477,7750577,7758577,7764677,7772777, 56 7774777,7778777,7782877,7783877,7791977,7794977,7807087,7819187,7820287,7821287,7831387,7832387, 57 7838387,7843487,7850587,7856587,7865687,7867687,7868687,7873787,7884887,7891987,7897987,7913197, 58 7916197,7930397,7933397,7935397,7938397,7941497,7943497,7949497,7957597,7958597,7960697,7977797, 59 7984897,7985897,7987897,7996997,9002009,9015109,9024209,9037309,9042409,9043409,9045409,9046409, 60 9049409,9067609,9073709,9076709,9078709,9091909,9095909,9103019,9109019,9110119,9127219,9128219, 61 9136319,9149419,9169619,9173719,9174719,9179719,9185819,9196919,9199919,9200029,9209029,9212129, 62 9217129,9222229,9223229,9230329,9231329,9255529,9269629,9271729,9277729,9280829,9286829,9289829, 63 9318139,9320239,9324239,9329239,9332339,9338339,9351539,9357539,9375739,9384839,9397939,9400049, 64 9414149,9419149,9433349,9439349,9440449,9446449,9451549,9470749,9477749,9492949,9493949,9495949, 65 9504059,9514159,9526259,9529259,9547459,9556559,9558559,9561659,9577759,9583859,9585859,9586859, 66 9601069,9602069,9604069,9610169,9620269,9624269,9626269,9632369,9634369,9645469,9650569,9657569, 67 9670769,9686869,9700079,9709079,9711179,9714179,9724279,9727279,9732379,9733379,9743479,9749479, 68 9752579,9754579,9758579,9762679,9770779,9776779,9779779,9781879,9782879,9787879,9788879,9795979, 69 9801089,9807089,9809089,9817189,9818189,9820289,9822289,9836389,9837389,9845489,9852589,9871789, 70 9888889,9889889,9896989,9902099,9907099,9908099,9916199,9918199,9919199,9921299,9923299,9926299, 71 9927299,9931399,9932399,9935399,9938399,9957599,9965699,9978799,9980899,9981899,9989899,-1 72 }; 73 int main() 74 { 75 // freopen("2.txt","w",stdout); 76 int i; 77 while(sc(a, b)!=EOF) 78 { 79 b = b > 9989899 ? 9989899 : b; 80 for(i = 0; arr[i] != -1; i++) 81 { 82 if(arr[i] >= a && arr[i] <= b) 83 pf(arr[i]); 84 if(arr[i] > b) 85 break; 86 } 87 printf(" "); 88 } 89 return 0; 90 }
1 #include <iostream> 2 #include <cstdio> 3 #define pf(x) printf("%d ", x) 4 using namespace std; 5 int a, b; 6 int arr[]= {2,3,5,7,11,101,131,151,181,191, 7 313,353,373,383,727,757,787,797,919,929, 8 10301,10501,10601,11311,11411,12421,12721,12821,13331,13831, 9 13931,14341,14741,15451,15551,16061,16361,16561,16661,17471, 10 17971,18181,18481,19391,19891,19991,30103,30203,30403,30703, 11 30803,31013,31513,32323,32423,33533,34543,34843,35053,35153, 12 35353,35753,36263,36563,37273,37573,38083,38183,38783,39293, 13 70207,70507,70607,71317,71917,72227,72727,73037,73237,73637, 14 74047,74747,75557,76367,76667,77377,77477,77977,78487,78787, 15 78887,79397,79697,79997,90709,91019,93139,93239,93739,94049, 16 94349,94649,94849,94949,95959,96269,96469,96769,97379,97579, 17 97879,98389,98689,1003001,1008001,1022201,1028201,1035301,1043401,1055501, 18 1062601,1065601,1074701,1082801,1085801,1092901,1093901,1114111,1117111,1120211, 19 1123211,1126211,1129211,1134311,1145411,1150511,1153511,1160611,1163611,1175711, 20 1177711,1178711,1180811,1183811,1186811,1190911,1193911,1196911,1201021,1208021, 21 1212121,1215121,1218121,1221221,1235321,1242421,1243421,1245421,1250521,1253521, 22 1257521,1262621,1268621,1273721,1276721,1278721,1280821,1281821,1286821,1287821, 23 1300031,1303031,1311131,1317131,1327231,1328231,1333331,1335331,1338331,1343431, 24 1360631,1362631,1363631,1371731,1374731,1390931,1407041,1409041,1411141,1412141, 25 1422241,1437341,1444441,1447441,1452541,1456541,1461641,1463641,1464641,1469641, 26 1486841,1489841,1490941,1496941,1508051,1513151,1520251,1532351,1535351,1542451, 27 1548451,1550551,1551551,1556551,1557551,1565651,1572751,1579751,1580851,1583851, 28 1589851,1594951,1597951,1598951,1600061,1609061,1611161,1616161,1628261,1630361, 29 1633361,1640461,1643461,1646461,1654561,1657561,1658561,1660661,1670761,1684861, 30 1685861,1688861,1695961,1703071,1707071,1712171,1714171,1730371,1734371,1737371, 31 1748471,1755571,1761671,1764671,1777771,1793971,1802081,1805081,1820281,1823281, 32 1824281,1826281,1829281,1831381,1832381,1842481,1851581,1853581,1856581,1865681, 33 1876781,1878781,1879781,1880881,1881881,1883881,1884881,1895981,1903091,1908091, 34 1909091,1917191,1924291,1930391,1936391,1941491,1951591,1952591,1957591,1958591, 35 1963691,1968691,1969691,1970791,1976791,1981891,1982891,1984891,1987891,1988891, 36 1993991,1995991,1998991,3001003,3002003,3007003,3016103,3026203,3064603,3065603, 37 3072703,3073703,3075703,3083803,3089803,3091903,3095903,3103013,3106013,3127213, 38 3135313,3140413,3155513,3158513,3160613,3166613,3181813,3187813,3193913,3196913, 39 3198913,3211123,3212123,3218123,3222223,3223223,3228223,3233323,3236323,3241423, 40 3245423,3252523,3256523,3258523,3260623,3267623,3272723,3283823,3285823,3286823, 41 3288823,3291923,3293923,3304033,3305033,3307033,3310133,3315133,3319133,3321233, 42 3329233,3331333,3337333,3343433,3353533,3362633,3364633,3365633,3368633,3380833, 43 3391933,3392933,3400043,3411143,3417143,3424243,3425243,3427243,3439343,3441443, 44 3443443,3444443,3447443,3449443,3452543,3460643,3466643,3470743,3479743,3485843, 45 3487843,3503053,3515153,3517153,3528253,3541453,3553553,3558553,3563653,3569653, 46 3586853,3589853,3590953,3591953,3594953,3601063,3607063,3618163,3621263,3627263, 47 3635363,3643463,3646463,3670763,3673763,3680863,3689863,3698963,3708073,3709073, 48 3716173,3717173,3721273,3722273,3728273,3732373,3743473,3746473,3762673,3763673, 49 3765673,3768673,3769673,3773773,3774773,3781873,3784873,3792973,3793973,3799973, 50 3804083,3806083,3812183,3814183,3826283,3829283,3836383,3842483,3853583,3858583, 51 3863683,3864683,3867683,3869683,3871783,3878783,3893983,3899983,3913193,3916193, 52 3918193,3924293,3927293,3931393,3938393,3942493,3946493,3948493,3964693,3970793, 53 3983893,3991993,3994993,3997993,3998993,7014107,7035307,7036307,7041407,7046407, 54 7057507,7065607,7069607,7073707,7079707,7082807,7084807,7087807,7093907,7096907, 55 7100017,7114117,7115117,7118117,7129217,7134317,7136317,7141417,7145417,7155517, 56 7156517,7158517,7159517,7177717,7190917,7194917,7215127,7226227,7246427,7249427, 57 7250527,7256527,7257527,7261627,7267627,7276727,7278727,7291927,7300037,7302037, 58 7310137,7314137,7324237,7327237,7347437,7352537,7354537,7362637,7365637,7381837, 59 7388837,7392937,7401047,7403047,7409047,7415147,7434347,7436347,7439347,7452547, 60 7461647,7466647,7472747,7475747,7485847,7486847,7489847,7493947,7507057,7508057, 61 7518157,7519157,7521257,7527257,7540457,7562657,7564657,7576757,7586857,7592957, 62 7594957,7600067,7611167,7619167,7622267,7630367,7632367,7644467,7654567,7662667, 63 7665667,7666667,7668667,7669667,7674767,7681867,7690967,7693967,7696967,7715177, 64 7718177,7722277,7729277,7733377,7742477,7747477,7750577,7758577,7764677,7772777, 65 7774777,7778777,7782877,7783877,7791977,7794977,7807087,7819187,7820287,7821287, 66 7831387,7832387,7838387,7843487,7850587,7856587,7865687,7867687,7868687,7873787, 67 7884887,7891987,7897987,7913197,7916197,7930397,7933397,7935397,7938397,7941497, 68 7943497,7949497,7957597,7958597,7960697,7977797,7984897,7985897,7987897,7996997, 69 9002009,9015109,9024209,9037309,9042409,9043409,9045409,9046409,9049409,9067609, 70 9073709,9076709,9078709,9091909,9095909,9103019,9109019,9110119,9127219,9128219, 71 9136319,9149419,9169619,9173719,9174719,9179719,9185819,9196919,9199919,9200029, 72 9209029,9212129,9217129,9222229,9223229,9230329,9231329,9255529,9269629,9271729, 73 9277729,9280829,9286829,9289829,9318139,9320239,9324239,9329239,9332339,9338339, 74 9351539,9357539,9375739,9384839,9397939,9400049,9414149,9419149,9433349,9439349, 75 9440449,9446449,9451549,9470749,9477749,9492949,9493949,9495949,9504059,9514159, 76 9526259,9529259,9547459,9556559,9558559,9561659,9577759,9583859,9585859,9586859, 77 9601069,9602069,9604069,9610169,9620269,9624269,9626269,9632369,9634369,9645469, 78 9650569,9657569,9670769,9686869,9700079,9709079,9711179,9714179,9724279,9727279, 79 9732379,9733379,9743479,9749479,9752579,9754579,9758579,9762679,9770779,9776779, 80 9779779,9781879,9782879,9787879,9788879,9795979,9801089,9807089,9809089,9817189, 81 9818189,9820289,9822289,9836389,9837389,9845489,9852589,9871789,9888889,9889889, 82 9896989,9902099,9907099,9908099,9916199,9918199,9919199,9921299,9923299,9926299, 83 9927299,9931399,9932399,9935399,9938399,9957599,9965699,9978799,9980899,9981899, 84 9989899 85 }; 86 int main() 87 { 88 int i; 89 while(cin >> a >> b) 90 { 91 if(b>9989899) b=9989899; 92 for(i = 0; arr[i] <= b; i++) 93 { 94 if(arr[i] >= a) 95 pf(arr[i]); 96 if(arr[i] == b) 97 break; 98 } 99 cout << endl; 100 } 101 return 0; 102 }
这个地方要注意越界的问题！！
AC代码：将最大值减小就可以了9989899
1 #include <iostream> 2 #include <cstdio> 3 #include <cmath> 4 #define sc(x,y) scanf("%d %d",&(x),&(y)) 5 #define pf(x) printf("%d ", x) 6 using namespace std; 7 int a, b; 8 int is_prime(int x); 9 int is_hui(int y); 10 int main() 11 { 12 int i; 13 while(sc(a,b)!=EOF) 14 { 15 for(i = a; i <= b; i++) 16 { 17 if(i==2 || i==3 || i==5 || i==7) 18 pf(i); 19 else if(is_hui(i)) 20 { 21 if(is_prime(i)) 22 pf(i); 23 } 24 } 25 } 26 return 0; 27 } 28 int is_prime(int x) 29 { 30 int j; 31 for(j = 3; j <= sqrt(x); j+=2) 32 { 33 if(x%j==0) 34 return 0; 35 } 36 return 1; 37 } 38 int is_hui(int y) 39 { 40 if(!(y&1)) return 0; 41 int val = y;//设置临时变量保存y，因为y在后面需要变化 42 // cout << y << " YY "; 43 int yy=0; 44 while(y) 45 { 46 yy=yy*10+y%10; 47 y/=10; 48 } 49 // cout << yy << endl; 50 if(yy == val) 51 return 1; 52 return 0; 53 }
不过，打表绝对是一个很重要的解题方法，可以使时间缩减
1.N皇后问题
1 #include <iostream> 2 #include <cmath> 3 using namespace std; 4 int x[11], n, N; 5 int Queen[] = {0, 1, 0, 0, 2, 10, 4, 40, 92, 352, 724}; 6 int place(int j) 7 { 8 int i; 9 for(i = 1; i < j; i++) 10 if(x[i] == x[j] || abs(j-i) == abs(x[j] - x[i])) 11 return false; 12 return true; 13 } 14 void queen(int t) 15 { 16 int k; 17 if(t > n) 18 N++; 19 else 20 { 21 for(k = 1; k <= n; k++) 22 { 23 x[t] = k; 24 if(place(t)) 25 queen(t + 1); 26 } 27 } 28 } 29 int main() 30 { 31 // int hang[11]; 32 // for(n = 1; n <= 10; n++) 33 // { 34 // N = 0; 35 // queen(1); 36 // hang[n] = N; 37 // } 38 while(cin >> n, n) 39 cout << Queen[n] << endl; 40 // cout << hang[n] << endl; 41 return 0; 42 }
2.素数问题
1 int prime[MAX] = {0}; //素数表 2 void InitPrime(); 3 void InitPrime() 4 { 5 int i, j; 6 for(i = 3; i <= MAX; i++) 7 { 8 if(!(i&1))continue; //奇偶判断 9 for(j = 3; j*j <= i; j += 2) 10 { 11 if(i%j == 0) 12 break; 13 } 14 if(j*j > i) 15 { 16 prime[i] = 1; 17 } 18 } 19 prime[2] = 1; 20 }