## 10200 - Prime Time

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Wei-Ming Chen
Experienced poster
Posts: 122
Joined: Sun Nov 13, 2005 10:25 am
Location: Taiwan
Maybe you can first run 0 to 10000 and save it
Then only to check how much between a and b

serur
A great helper
Posts: 251
Joined: Thu Feb 23, 2006 11:30 pm

### 10200

ACC - just read the previous clever messages!
Thank them all!

Mamet
New poster
Posts: 7
Joined: Tue Mar 14, 2006 12:59 am

### 10200

Hi people. I got PE in that program and when I run it i think it outputs in a correct way. Anyone knows the reason

kryptolus
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Posts: 16
Joined: Sun Mar 19, 2006 9:36 am
Location: New York
What if you change %5.2f to %.2f?

Mamet
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Posts: 7
Joined: Tue Mar 14, 2006 12:59 am

### Thx

Thx a lot! I found this function on the Internet but didn't know very well how it worked. Now I got AC. Thx a lot!!!

kryptolus
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Posts: 16
Joined: Sun Mar 19, 2006 9:36 am
Location: New York

### Re: Thx

Mamet wrote:Thx a lot! I found this function on the Internet but didn't know very well how it worked. Now I got AC. Thx a lot!!!
The '5' in %5.2f means add extra spaces if the whole part of the number is less than 5 digits long. So if you print 99, 3 extra spaces are added in front so that the output is always at least 5 characters long.

yogeshgo05
New poster
Posts: 47
Joined: Sun Nov 27, 2005 12:43 pm

### 10200 tle

hi guys how do u ... come over since u r supposed generate upto 100000000 prime numbers ... i use a bool array i get tle...
wat is limit bool array could some body tell me &
r u people just genrating numbers b/w two i/p;

Timo
Learning poster
Posts: 70
Joined: Tue Oct 11, 2005 2:44 am
Location: Indonesia
you don't have to generate up to 100000000 prime.
Only sqrt(100000000) = 10000 prime

"Life is more beautiful with algorithm"

arsalan_mousavian
Experienced poster
Posts: 111
Joined: Mon Jan 09, 2006 6:19 pm
Location: Tehran, Iran
Contact:
dear yogeshgo05 i wonder how you didn't get MLE because :
if we would be able to calculate all the the primes less than 10^9 using boolean array in a reasonable time ,we need 1000 MB memory that is much more than memory limitation on OJ ( 32 MB )

fpavetic
Learning poster
Posts: 51
Joined: Sat Mar 04, 2006 8:00 pm
arsalan_mousavian wrote:dear yogeshgo05 i wonder how you didn't get MLE because :
if we would be able to calculate all the the primes less than 10^9 using boolean array in a reasonable time ,we need 1000 MB memory that is much more than memory limitation on OJ ( 32 MB )
it is 10^8. and you can generate them using bit operations to use one bit instead of one byte for marking a prime number. so total memory is
100000000 / 1024 / 1024 / 8 = 11.92 Mb. but time is the problem.

Timo
Learning poster
Posts: 70
Joined: Tue Oct 11, 2005 2:44 am
Location: Indonesia
I think for this problem not need to generate up to 10^8 prime, but only 10^4 prime.
"Life is more beautiful with algorithm"

fpavetic
Learning poster
Posts: 51
Joined: Sat Mar 04, 2006 8:00 pm
Timo wrote:I think for this problem not need to generate up to 10^8 prime, but only 10^4 prime.
i agree ( i have solved this problem long time ago ). but i am just saying that memory is not the issue

arsalan_mousavian
Experienced poster
Posts: 111
Joined: Mon Jan 09, 2006 6:19 pm
Location: Tehran, Iran
Contact:
fpavetic wrote:
Timo wrote:I think for this problem not need to generate up to 10^8 prime, but only 10^4 prime.
i agree ( i have solved this problem long time ago ). but i am just saying that memory is not the issue
oops , i give up i also solved this problem long time age , sorry for my fault

Dickon
New poster
Posts: 4
Joined: Thu Jun 15, 2006 4:10 am

### 10200(time limited~help)

my code is always time limited,
can someone give me suggestion?

my code is:
#include<stdio.h>
#include<math.h>
int main()
{
int j=0,temp,m=0,y=0;
float i,a,b,k=0.00,s=0.00,c=0.00;
int p[1230]={2,3,5,7,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97,101,103,
107,109,113,127,131,137,139,149,151,157,163,167,173,179,181,191,193,197,199,211,223,227,
229,233,239,241,251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,353,
359,367,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,
491,499,503,509,521,523,541,547,557,563,569,571,577,587,593,599,601,607,613,617,619,631,
641,643,647,653,659,661,673,677,683,691,701,709,719,727,733,739,743,751,757,761,769,773,
787,797,809,811,821,823,827,829,839,853,857,859,863,877,881,883,887,907,911,919,929,937,
941,947,953,967,971,977,983,991,997,1009,1013,1019,1021,1031,1033,1039,1049,1051,1061,
1063,1069,1087,1091,1093,1097,1103,1109,1117,1123,1129,1151,1153,1163,1171,1181,1187,
1193,1201,1213,1217,1223,1229,1231,1237,1249,1259,1277,1279,1283,1289,1291,1297,1301,
1303,1307,1319,1321,1327,1361,1367,1373,1381,1399,1409,1423,1427,1429,1433,1439,1447,
1451,1453,1459,1471,1481,1483,1487,1489,1493,1499,1511,1523,1531,1543,1549,1553,1559,
1567,1571,1579,1583,1597,1601,1607,1609,1613,1619,1621,1627,1637,1657,1663,1667,1669,
1693,1697,1699,1709,1721,1723,1733,1741,1747,1753,1759,1777,1783,1787,1789,1801,1811,
1823,1831,1847,1861,1867,1871,1873,1877,1879,1889,1901,1907,1913,1931,1933,1949,1951,
1973,1979,1987,1993,1997,1999,2003,2011,2017,2027,2029,2039,2053,2063,2069,2081,2083,
2087,2089,2099,2111,2113,2129,2131,2137,2141,2143,2153,2161,2179,2203,2207,2213,2221,
2237,2239,2243,2251,2267,2269,2273,2281,2287,2293,2297,2309,2311,2333,2339,2341,2347,
2351,2357,2371,2377,2381,2383,2389,2393,2399,2411,2417,2423,2437,2441,2447,2459,2467,
2473,2477,2503,2521,2531,2539,2543,2549,2551,2557,2579,2591,2593,2609,2617,2621,2633,
2647,2657,2659,2663,2671,2677,2683,2687,2689,2693,2699,2707,2711,2713,2719,2729,2731,
2741,2749,2753,2767,2777,2789,2791,2797,2801,2803,2819,2833,2837,2843,2851,2857,2861,
2879,2887,2897,2903,2909,2917,2927,2939,2953,2957,2963,2969,2971,2999,3001,3011,3019,
3023,3037,3041,3049,3061,3067,3079,3083,3089,3109,3119,3121,3137,3163,3167,3169,3181,
3187,3191,3203,3209,3217,3221,3229,3251,3253,3257,3259,3271,3299,3301,3307,3313,3319,
3323,3329,3331,3343,3347,3359,3361,3371,3373,3389,3391,3407,3413,3433,3449,3457,3461,
3463,3467,3469,3491,3499,3511,3517,3527,3529,3533,3539,3541,3547,3557,3559,3571,3581,
3583,3593,3607,3613,3617,3623,3631,3637,3643,3659,3671,3673,3677,3691,3697,3701,3709,
3719,3727,3733,3739,3761,3767,3769,3779,3793,3797,3803,3821,3823,3833,3847,3851,3853,
3863,3877,3881,3889,3907,3911,3917,3919,3923,3929,3931,3943,3947,3967,3989,4001,4003,
4007,4013,4019,4021,4027,4049,4051,4057,4073,4079,4091,4093,4099,4111,4127,4129,4133,
4139,4153,4157,4159,4177,4201,4211,4217,4219,4229,4231,4241,4243,4253,4259,4261,4271,
4273,4283,4289,4297,4327,4337,4339,4349,4357,4363,4373,4391,4397,4409,4421,4423,4441,
4447,4451,4457,4463,4481,4483,4493,4507,4513,4517,4519,4523,4547,4549,4561,4567,4583,
4591,4597,4603,4621,4637,4639,4643,4649,4651,4657,4663,4673,4679,4691,4703,4721,4723,
4729,4733,4751,4759,4783,4787,4789,4793,4799,4801,4813,4817,4831,4861,4871,4877,4889,
4903,4909,4919,4931,4933,4937,4943,4951,4957,4967,4969,4973,4987,4993,4999,5003,5009,
5011,5021,5023,5039,5051,5059,5077,5081,5087,5099,5101,5107,5113,5119,5147,5153,5167,
5171,5179,5189,5197,5209,5227,5231,5233,5237,5261,5273,5279,5281,5297,5303,5309,5323,
5333,5347,5351,5381,5387,5393,5399,5407,5413,5417,5419,5431,5437,5441,5443,5449,5471,
5477,5479,5483,5501,5503,5507,5519,5521,5527,5531,5557,5563,5569,5573,5581,5591,5623,
5639,5641,5647,5651,5653,5657,5659,5669,5683,5689,5693,5701,5711,5717,5737,5741,5743,
5749,5779,5783,5791,5801,5807,5813,5821,5827,5839,5843,5849,5851,5857,5861,5867,5869,
5879,5881,5897,5903,5923,5927,5939,5953,5981,5987,6007,6011,6029,6037,6043,6047,6053,
6067,6073,6079,6089,6091,6101,6113,6121,6131,6133,6143,6151,6163,6173,6197,6199,6203,
6211,6217,6221,6229,6247,6257,6263,6269,6271,6277,6287,6299,6301,6311,6317,6323,6329,
6337,6343,6353,6359,6361,6367,6373,6379,6389,6397,6421,6427,6449,6451,6469,6473,6481,
6491,6521,6529,6547,6551,6553,6563,6569,6571,6577,6581,6599,6607,6619,6637,6653,6659,
6661,6673,6679,6689,6691,6701,6703,6709,6719,6733,6737,6761,6763,6779,6781,6791,6793,
6803,6823,6827,6829,6833,6841,6857,6863,6869,6871,6883,6899,6907,6911,6917,6947,6949,
6959,6961,6967,6971,6977,6983,6991,6997,7001,7013,7019,7027,7039,7043,7057,7069,7079,
7103,7109,7121,7127,7129,7151,7159,7177,7187,7193,7207,7211,7213,7219,7229,7237,7243,
7247,7253,7283,7297,7307,7309,7321,7331,7333,7349,7351,7369,7393,7411,7417,7433,7451,
7457,7459,7477,7481,7487,7489,7499,7507,7517,7523,7529,7537,7541,7547,7549,7559,7561,
7573,7577,7583,7589,7591,7603,7607,7621,7639,7643,7649,7669,7673,7681,7687,7691,7699,
7703,7717,7723,7727,7741,7753,7757,7759,7789,7793,7817,7823,7829,7841,7853,7867,7873,
7877,7879,7883,7901,7907,7919,7927,7933,7937,7949,7951,7963,7993,8009,8011,8017,8039,
8053,8059,8069,8081,8087,8089,8093,8101,8111,8117,8123,8147,8161,8167,8171,8179,8191,
8209,8219,8221,8231,8233,8237,8243,8263,8269,8273,8287,8291,8293,8297,8311,8317,8329,
8353,8363,8369,8377,8387,8389,8419,8423,8429,8431,8443,8447,8461,8467,8501,8513,8521,
8527,8537,8539,8543,8563,8573,8581,8597,8599,8609,8623,8627,8629,8641,8647,8663,8669,
8677,8681,8689,8693,8699,8707,8713,8719,8731,8737,8741,8747,8753,8761,8779,8783,8803,
8807,8819,8821,8831,8837,8839,8849,8861,8863,8867,8887,8893,8923,8929,8933,8941,8951,
8963,8969,8971,8999,9001,9007,9011,9013,9029,9041,9043,9049,9059,9067,9091,9103,9109,
9127,9133,9137,9151,9157,9161,9173,9181,9187,9199,9203,9209,9221,9227,9239,9241,9257,
9277,9281,9283,9293,9311,9319,9323,9337,9341,9343,9349,9371,9377,9391,9397,9403,9413,
9419,9421,9431,9433,9437,9439,9461,9463,9467,9473,9479,9491,9497,9511,9521,9533,9539,
9547,9551,9587,9601,9613,9619,9623,9629,9631,9643,9649,9661,9677,9679,9689,9697,9719,
9721,9733,9739,9743,9749,9767,9769,9781,9787,9791,9803,9811,9817,9829,9833,9839,9851,
9857,9859,9871,9883,9887,9901,9907,9923,9929,9931,9941,9949,9967,9973};

while(scanf("%f%f",&a,&b)!=EOF){

if(b<40){
printf("100.00\n");
}

else{

for(i=a;i<=b;i++){
temp=i*i+i+41;

while(pow(temp,0.5)>=p[y]&&y<=1228){

if(temp%p[y]==0){
m++;
break;
}
y++;
}

if(m==0){
c++;
}
m=0;
y=0;
}

printf("%.2f\n",(c/(b-a+1))*100);
c=0.00;
}
}

return 0;
}

Moheeb
New poster
Posts: 21
Joined: Fri May 05, 2006 9:08 am
Dickon wrote:
my code is always time limited,
can someone give me suggestion?

why u r doing the same thing again and again,? u can do lthe following:

for(i =0 ;i<=10000;i++){
n=i*i + i + 41 ;
flag[ i ] = prime ( n) ; // 1 if n is prime ,0 otherwise ;
}
now the rest is trivial ,do ....
while( cin >> a >>b) {
c = 0 ;
for( i =a i <= b ; i++)
if( flag )
c ++ ;

now use the formula .

hope u can do it by urself .