402D Upgrading Array

See: https://github.com/CyberZHG/blog/issues/10

#include <cstdio>#include <cstring>#include <set>#include <algorithm>using namespace std;const int MAXN = 5000 + 10;int n, m;int a[MAXN], b, g[MAXN];set<int> bad;int gcd(int a, int b){    return b == 0 ? a : gcd(b, a % b);}int getScore(int x){    int score = 0;    while ((x & 1) == 0)    {        x >>= 1;        bad.find(2) == bad.end() ? ++score : --score;    }    for (int i = 3; i * i <= x && x != 1; i += 2)    {        while (x % i == 0)        {            bad.find(i) == bad.end() ? ++score : --score;            x /= i;        }    }    if (x != 1)    {        bad.find(x) == bad.end() ? ++score : --score;    }    return score;}int main(){    scanf("%d%d", &n, &m);    for (int i = 0; i < n; ++i)    {        scanf("%d", &a[i]);        if (i == 0)        {            g[0] = a[0];        }        else        {            g[i] = gcd(g[i - 1], a[i]);        }    }    for (int i = 0; i < m; ++i)    {        scanf("%d", &b);        bad.insert(b);    }    int div = 1, ans = 0;    for (int i = n - 1; i >= 0; --i)    {        if (getScore(g[i] / div) <= 0)        {            div = g[i];        }        ans += getScore(a[i] / div);    }    printf("%d\n", ans);    return 0;}