hdu-5104

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打表后，枚举出i,j,k = n-i-j 即可

#include<stdio.h>#include<iostream>#include<math.h>#include<stdlib.h>#include<ctype.h>#include<algorithm>#include<vector>#include<string.h>#include<queue>#include<stack>#include<set>#include<map>#include<sstream>#include<time.h>#include<utility>#include<malloc.h>#include<stdexcept>using namespace std;int is_prime(int n ){    for(int i=2 ;i*i<=n;i++ )    {        if ( n % i ==0)            return 0;    }    return 1;}int n,m;int  main (){    int prime[10005];    memset(prime,0,sizeof(prime));    for(int i=2 ;i<=10002;i++)    {        if ( is_prime(i) )            prime[i] = 1;    }    while (cin>>n)    {        int num =0;        for(int i=2 ;i<=n;i++)            for(int j=i ;j<=(n-i)/2;j++)            {                if (prime[i] && prime[j]&& prime[n-i-j])                {                    num++;                }            }        cout<<num<<endl;    }    return 0;}

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