HDU 2161 Primes

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刷专题，从水题刷起……

水题不能一Y也真是……

1和2，在这题里输出no，其他素数输出yes。注意别用while(1)，反正我OLE了一发……

#include<map>#include<set>#include<list>#include<stack>#include<deque>#include<queue>#include<vector>#include<sstream>#include<iomanip>#include<iostream>#include<math.h>#include<ctype.h>#include<stdio.h>#include<stdlib.h>#include<string.h>#include<algorithm>#include<functional>#define CPY(A,B)memcpy(A,B,sizeof(A))#define fin freopen("in.txt","r",stdin)#define fout freopen("out.txt","w",stdout)typedef long long LL;typedef unsigned long long uLL;const int MOD=1e9+7;const int INF=0x3f3f3f3f;const LL INFF=0x3f3f3f3f3f3f3f3fLL;const double OO=1e20;const double EPS=1e-9;const double PI=acos (-1.0);int dx[]= {0,1,0,-1};int dy[]= {1,0,-1,0};using namespace std;int gcd (const LL &a,const LL &b) {    return b==0?a:gcd (b,a%b);}inline int dcmp (double a,double b) {    if (fabs (a-b) <EPS) { return 0; }    return a>b;}const int M=16016;#define MAXN 16016#define MAXL 16016int prime[MAXN];int check[MAXL];void Init() {    int tot = 0;    memset (check, 0, sizeof (check) );    for (int i = 2; i < MAXL; ++i) {        if (!check[i]) {            prime[tot++] = i;        }        for (int j = 0; j < tot; ++j) {            if (i * prime[j] > MAXL) {                break;            }            check[i*prime[j]] = 1;            if (i % prime[j] == 0) {                break;            }        }    }}int main() {    Init();    int cas=0,n;    prime[0]=3;//first is 2, so change it to 3    while (cin>>n) {        if (n<=0) break;        for (int i=0; i<M; ++i) {            if (n<prime[i]) {                printf ("%d: no\n",++cas);break;            } else if (n==prime[i]) {                printf ("%d: yes\n",++cas);break;            }        }    }    return 0;}

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