39: The nth small prime number

39: The nth small prime number
Total time limit: 1000ms memory limit: 65536kB
Describe
Enter a positive integer n to find the small prime number of nth.
Input
A positive integer of not more than 10000 n.
Output
The nth small prime number.
Sample input
10
Sample output
29

Method One: The Honest enumeration count finds to the nth prime number and then outputs.

1#include <stdio.h>2#include <math.h>3 intMainintargcChar*argv[])4 {5     LongI,n,count;6     Longj,flag,t;7scanf"%d", &n);//need to find nth prime number8Count=0;//already looking up to count a9     TenI=2; One     //I gradually increased from 2 onwards. Determine if the value of I is a prime number and count A      while(count<N) -     { -         //Judging whether I prime thej=2; flag=0; t=sqrt (i); -          while(j<=t) -         { -             if(i%j==0) +             { -flag=1; +                  Break; A             } atJ + +; -         } -         //If I is a prime number, Count counter plus 1 -         if(flag==0) count++; -i++;//ready to judge the next number -     } inprintf"%d\n", I-1); -     return 0; to}

Method Two: Offline calculation, first print out 10000 prime numbers into the array, and then ... Oh

Modify the above code slightly to generate prime numbers and output them to the file:

1#include <stdio.h>2#include <math.h>3 intMainintargcChar*argv[])4 {5     LongI,n,count;6     Longj,flag,t;7Freopen ("39.out","W", stdout);8     //scanf ("%d", &n); //need to find nth prime number9n=10003;TenCount=0;//already looking up to count a One      AI=2; -     //I gradually increased from 2 onwards. Determine if the value of I is a prime number and count -      while(count<N) the     { -         //Judging whether I prime -j=2; flag=0; t=sqrt (i); -          while(j<=t) +         { -             if(i%j==0) +             { Aflag=1; at                  Break; -             } -J + +; -         } -         //If I is a prime number, Count counter plus 1 -         if(flag==0) in         { -count++; toprintf"%d,", i); +         } -i++;//ready to judge the next number the     } *     //printf ("%d\n", i-1); $     return 0;Panax Notoginseng}

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Then copy the data from the file into the code and construct the array. Hey, whoa.

1#include <stdio.h>2 intMainintargcChar*argv[])3 {4     Longa[10003]=5 {//In order to open the page faster, do not finish the data.6         2,3,5,7, One, -, -, +, at, in, to,......7     };8     intN;9scanf"%d",&n);Tenprintf"%d\n", a[n-1]); One     return 0; A}

Yes, opportunistic.

39: The nth small prime number