1404 - Prime k-tuple

54s的时限暴力吧！

#include<cstdio>
#include<vector>
#include<cstring>
#include<iostream>
using namespace std;

const int maxn = 45000;
int prime[maxn], plen = 0;
bool vis[maxn];
void mklist() {
    memset(vis, 0, sizeof(vis));
    plen = 0;
    for(int i = 2; i * i < maxn; ++i) {
        if(!vis[i]) {
            for(int j = i; i * j < maxn; ++j) {
                vis[i * j] = true;
            }
        }
    }
    for(int i = 2; i < maxn; ++i) if(!vis[i]) prime[plen++] = i;
}

bool test(int x) {
    for(int i = 0; i < plen && prime[i] * prime[i] <= x; ++i) {
        if(x % prime[i] == 0) return false;
    }
    return true;
}

int main() {
    mklist();
    int T;
    cin >> T;
    for(int kase = 1; kase <= T; ++kase) {
        int a, b, k, s;
        vector<int> p;
        cin >> a >> b >> k >> s;
        for(int i = a; i <= b; ++i) {
            if(test(i)) p.push_back(i);
        }
        int ans = 0;
        for(int i = 0; i + k - 1 < p.size(); ++i) {
            if(p[i + k - 1] - p[i] == s) ++ans;
        }
        cout << ans << endl;
    }
    return 0;
}