1501131824-Blue Bridge cup-algorithm training Torry Puzzle (basic type)

Algorithm Training Torry Puzzle (basic type) time limit: 1.0s memory limit: 512.0MBProblem description Torry from childhood love mathematics. One day, the teacher told him, like 2, 3, 5, 7 ... Such numbers are called prime numbers. Torry suddenly thought of a problem, the first 10, 100, 1000, 10000 ... What is the product of a prime number? He told the teacher the question. The teacher was stunned and couldn't answer it. So Torry turned to the programmer, and asked you to calculate the product of the first n prime numbers. However, considering that you are only in touch with programming soon, Torry as long as you figure out the value of 50000 on the modulo. The input format contains only a positive integer n, where n<=100000. The output format outputs a row, which is the value of the product modulo 50000 of the first n prime numbers. Example input 1 Sample output 2 Thinking of solving problemsbecause I do not know what the 100,000th prime number is, so we can first use the larger n when the end of the table to 0--n direct prime numbers, and then starting from 0 to judge if the prime number is multiplied and j + +, you can enter the 100000来 to determine which numbers to cut off, and then modify the program's N. Note that the answer requires a 64-bit int. This problem also examines the congruence theorem. C code

#include <stdio.h> #include <string.h>int a[11000000],b[110000];int main () {int n;int i,j,k;__int64 answer; scanf ("%d", &n), memset (A,0,sizeof (a)), A[0]=a[1]=1;for (i=0;i<10000000;i++) {if (A[i])    continue;for (j=i+ i;j<10000000;j+=i)    a[j]=1;} Answer=1;for (i=0,j=0;i<10000000&&j<n;i++)//Because the output nth and J is starting from 0, so use < is good     if (a[i]==0)    {        b[j]=i;        Answer= ((answer%50000) * (b[j]%50000))%50000;        Note that when an=49999,b[j]=49999, the product exceeds the int type.         j + +;    } printf ("%d", I);   Since I do not know what the 100,000th prime number is, I test the input 100000 output I to when.     printf ("%i64d\n", answer); return 0;}

Java code

Package Torry Confusion; import java.util.scanner;public class main{public static void Main (string[] args) {Scanner input=new Scanner (system.in); int[] A=new int[1100000];int[] b=new int[110000];int n=input.nextint (); int I,j,k;long answer;a[0]= A[1]=1;for (i=0;i<1000000;i++) {if (a[i]==1) continue;for (j=i+i;j<1000000;j+=i) a[j]=1;} Answer=1;for (i=0,j=0;i<1000000&&j<n;i++) if (a[i]==0) {b[j]=i;answer= ((answer%50000) * (b[j]%50000))% 50000;j++;} System.out.println (answer);}}

1501131824-Blue Bridge cup-algorithm training Torry Puzzle (basic type)