Codeforces Round #421 (Div. 2), problem: (E) Mister B and Beacons on Field Solution In C/C++

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;
import java.util.TreeMap;

/**
* @author Don Li
*/
public class MisterBBeaconsField {

int N = (int) 2e6 + 10;
int SQRT = (int) (Math.sqrt(N) + 0.5);

int[] f = new int[N];
long nn, mm, ss;

long ans;
int[][] fs;
List<Long> bad = new ArrayList<>();

void solve() {
for (int i = 2; i < N; i++) {
if (f[i] == 0) {
f[i] = i;
for (int j = i * i; j < N && i <= SQRT; j += i) f[j] = i;
}
}

int T = in.nextInt();
while (T– > 0) {
int[] n = new int[3], m = new int[3], s = new int[3];
for (int i = 0; i < 3; i++) n[i] = in.nextInt();
for (int i = 0; i < 3; i++) m[i] = in.nextInt();
for (int i = 0; i < 3; i++) s[i] = in.nextInt();

s[0] *= 2;
nn = (long) n[0] * n[1] * n[2];
mm = (long) m[0] * m[1] * m[2];
ss = (long) s[0] * s[1] * s[2];

ans = 0;

fs = primeFactors(s);
dfs(0, 1);

bad.clear();
int[][] fn = primeFactors(n);
for (int i = 0; i < fn.length; i++) {
long v = fn[i][0];
for (int j = 0; j < fn[i][1]; j++) {
if (ss % v != 0) {
bad.add(v);
break;
}
v *= fn[i][0];
}
}
dfs2(0, 1, 0);

out.println(ans);
}
}

// iterate all the divisors of 2*s and count the number of divisors ≤ n
void dfs(int i, long v) {
if (i == fs.length) {
if (v <= nn) ans++;
return;
}
long mul = 1;
for (int j = 0; j <= fs[i][1]; j++) {
dfs(i + 1, v * mul);
mul *= fs[i][0];
}
}

// calc the number of k (such that gcd(n,k) | 2*s and 1≤k≤m) with inclusion-exclusion principle
void dfs2(int i, long v, int cnt) {
if (i == bad.size()) {
if (cnt == 0) ans += mm / v;
else ans -= mm / v;
return;
}
dfs2(i + 1, v, cnt);
dfs2(i + 1, v * bad.get(i), cnt ^ 1);
}

int[][] primeFactors(int[] a) {
TreeMap<Integer, Integer> map = new TreeMap<>();
for (int i = 0; i < 3; i++) {
int x = a[i];
while (x > 1 && x != f[x]) {
map.put(f[x], map.getOrDefault(f[x], 0) + 1);
x /= f[x];
}
if (x > 1) map.put(x, map.getOrDefault(x, 0) + 1);
}

int k = map.keySet().size();
int[][] cnt = new int[k][2];
int p = 0;
for (int x : map.keySet()) {
cnt[p][0] = x;
cnt[p][1] = map.get(x);
p++;
}
return cnt;
}

public static void main(String[] args) {
in = new FastScanner(new BufferedReader(new InputStreamReader(System.in)));
out = new PrintWriter(System.out);
new MisterBBeaconsField().solve();
out.close();
}

static FastScanner in;
static PrintWriter out;

static class FastScanner {
BufferedReader in;
StringTokenizer st;

public FastScanner(BufferedReader in) {
this.in = in;
}

public String nextToken() {
while (st == null || !st.hasMoreTokens()) {
try {
st = new StringTokenizer(in.readLine());
} catch (IOException e) {
e.printStackTrace();
}
}
return st.nextToken();
}

public int nextInt() {
return Integer.parseInt(nextToken());
}

public long nextLong() {
return Long.parseLong(nextToken());
}

public double nextDouble() {
return Double.parseDouble(nextToken());
}
}
}

China’s three telecom giants...

China’s telecommunications landscape is undergoing a monumental paradigm shift....

Fangzhou Ranked among 2025...

In a significant milestone for the digital healthcare sector,...

Why Everyone is Obsessed with the Sunset Projection LED Lamp

Are you tired of dealing with everyday frustrations that slow down your routine? We've all been...

China’s three telecom giants race into the AI token economy

China’s telecommunications landscape is undergoing a monumental paradigm shift. The nation's three state-owned telecom giants—China Mobile, China Telecom, and China Unicom—are aggressively moving beyond...

Why Everyone is Obsessed with the USB Rechargeable Lighter

Are you tired of dealing with everyday frustrations that slow down your routine? We've all been...

Why Everyone is Obsessed with the AeroPress Coffee Maker

Are you tired of dealing with everyday frustrations that slow down your routine? We've all been...

Fangzhou Ranked among 2025 Guangzhou AI Innovation “Most Promising Enterprises” for AI‑Powered Chronic Disease Services

In a significant milestone for the digital healthcare sector, Fangzhou has been officially ranked among the 2025 Guangzhou AI Innovation 'Most Promising Enterprises' list....

Why Everyone is Obsessed with the Universal Car Cleaning Gel

Are you tired of dealing with everyday frustrations that slow down your routine? We've all been...

Why Everyone is Obsessed with the Portable Door Lock for Travel

Are you tired of dealing with everyday frustrations that slow down your routine? We've all been...

Infected with TDSS and Google Keeps redirecting

Dealing with TDSS Rootkit Infections and Google Search Redirects Computer security is a continuous battle, and some threats are significantly more stubborn than others. A...

Why Everyone is Obsessed with the Portable Handheld Misting Fan

Are you tired of dealing with everyday frustrations that slow down your routine? We've all been...