hdu 2098 分拆素数和

来源：互联网发布：莱特币源码编辑：程序博客网时间：2024/06/05 13:15

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=2098
打表，二分。。

#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<vector>#include<map>#include<set>using std::cin;using std::cout;using std::endl;using std::find;using std::sort;using std::set;using std::map;using std::pair;using std::vector;using std::lower_bound;#define sz(c) (int)(c).size()#define all(c) (c).begin(), (c).end()#define iter(c) __typeof((c).begin())#define cls(arr,val) memset(arr,val,sizeof(arr))#define cpresent(c, e) (find(all(c), (e)) != (c).end())#define rep(i, n) for (int i = 0; i < (int)(n); i++)#define tr(c, i) for (iter(c) i = (c).begin(); i != (c).end(); ++i)#define pb(e) push_back(e)#define mp(a, b) make_pair(a, b)const int Max_N = 10010;typedef unsigned long long ull;struct PrimeSpilt {    int tot, prime[Max_N];    inline bool isPrime(int n) {        for(int i = 2; i * i <= n; i++) {            if(!(n % i)) return false;        }        return n != 1;    }    inline void init() {        tot = 0;        for(int i = 1;i < Max_N ;i++) {            if(isPrime(i)) prime[tot++] = i;        }    }    inline void work(int n) {        int ans = 0;        for(int i = 0;i < tot && prime[i] < n; i++) {            int p = lower_bound(prime + i, prime + tot, n - prime[i]) - prime;            if(prime[i] + prime[p] == n && i != p) ans++;        }        printf("%d\n", ans);    }}go;int main() {#ifdef LOCAL    freopen("in.txt","r",stdin);    freopen("out.txt","w+",stdout);#endif    int n;    go.init();    while(~scanf("%d", &n) && n) go.work(n);    return 0;}

0 0