POJ 2167 Irrelevant Elements (math,brute force)

#include <cstdio>#include <cstring>#include <vector>#include <algorithm>#include <iostream>#include <string>#include <vector>#include <cstdlib>#include <ctime>#include <cmath>#include <bitset>using namespace std;typedef long long LL;typedef unsigned long long ULL;typedef vector<int> VI;typedef vector<VI> VVI;const int maxn = 111111;const int N = 1111;const double eps = 1e-8;bitset<maxn + 100> vis;int p[maxn], size;void init() {int i, j;for (i = 2; i * i <= maxn; ++i)if (!vis[i])for (j = i * i; j <= maxn; vis[j] = 1, j += i);p[size++] = 2;for (i = 3; i <= maxn; i += 2)if (!vis[i])p[size++] = i;}int f[N], c[N], cnt;int X[maxn][15];void split(int n) {int i, t = n;memset(c, 0, sizeof(c));cnt = 0;for (i = 0; p[i] * p[i] <= n && i < size; ++i) {if (t % p[i] == 0) {f[cnt] = p[i];while (t % p[i] == 0)t /= p[i], c[cnt]++;++cnt;}}if (t > 1) {f[cnt] = t;c[cnt]++;++cnt;}}int cal(int n, int p) {LL k = 1;int cnt = 0;while (n >= k) {k *= p;cnt += (int) n / k;}return cnt;}int ans[maxn], k;int main() {ios::sync_with_stdio(false);init();int n, m;int i, j;while (~scanf("%d%d", &n, &m)) {split(m);for (i = 0; i < n; ++i) {for (j = 0; j < cnt; ++j) {X[i][j] = cal(i, f[j]);}}k = 0;int mi;for (i = 0; i < n; ++i) {mi = 1000000;for (j = 0; j < cnt; ++j) {mi = min(mi, (X[n - 1][j] - X[i][j] - X[n - i - 1][j]) / c[j]);if (mi<1)break;}if (mi>0)ans[k++] = i + 1;}printf("%d\n",k);for (i = 0; i < k; ++i) {printf("%d%c", ans[i], i == k - 1 ? '\n' : ' ');}}return 0;}