D - Anticube

https://atcoder.jp/contests/agc003/submissions/38309968

AtCoder/AGC003/D/D.cpp

@@ -0,0 +1,85 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <unordered_map>
+#include <utility>
+#include <vector>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+const int N = 1e5 + 5,
+          M = 3005;
+
+int n, ans;
+std::vector<long long> primes;
+bool not_prime[N];
+std::unordered_map<long long, int> map;
+std::vector<std::pair<long long, long long>> data;
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    for (int i = 2; i < M; i++) {
+        if (!not_prime[i]) primes.emplace_back(i);
+
+        for (auto p : primes) {
+            if (i * p >= M) break;
+
+            not_prime[i * p] = true;
+
+            if (i % p == 0) break;
+        }
+    }
+
+    cin >> n;
+
+    for (int i = 1; i <= n; i++) {
+        long long x, y = 1, z = 1;
+
+        cin >> x;
+
+        for (auto p : primes) {
+            if (p * p > x) break;
+
+            int t = 0;
+
+            while (x % p == 0) {
+                x /= p;
+                t++;
+            }
+
+            t %= 3;
+
+            if (t == 0) continue;
+
+            for (int k = 1; k <= t; k++) y *= p;
+            for (int k = 1; k <= 3 - t; k++) z *= p;
+        }
+
+        y *= x;
+
+        if (x > 1) {
+            long long t = std::sqrt(x);
+            if (t * t == x) z *= std::sqrt(x);
+            else z *= x * x;
+        }
+
+        map[y]++;
+        data.emplace_back(y, z);
+    }
+
+    ans = map[1] > 0;
+
+    for (auto o : data) {
+        if (o.first == 1) continue;
+
+        ans += std::max(map[o.first], map[o.second]);
+        map[o.first] = map[o.second] = 0;
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}