sqrt-decomposition

Author: a1fredbao

src/alfred/math/sqrt-decomposition.hpp

@@ -0,0 +1,17 @@
+#ifndef AFMT_SQRT_DECOMP
+#define AFMT_SQRT_DECOMP
+
+#include <array>
+#include <vector>
+
+template <class T>
+std::vector<std::array<T, 3>> sqrt_decomposit(T n) { // (l, r, v)
+    std::vector<std::array<T, 3>> ans;
+    for (T l = 1, r; l <= n; l = r + 1) {
+        r = n / (n / l);
+        ans.push_back({l, r, n / l});
+    }
+    return ans;
+}
+
+#endif

verify/verify-yosupo-math/yosupo-sqrt-decomposition.test.cpp

@@ -0,0 +1,19 @@
+// competitive-verifier: PROBLEM https://judge.yosupo.jp/problem/enumerate_quotients
+
+#include "../../src/alfred/config/io-sync-off.hpp"
+#include "../../src/alfred/math/sqrt-decomposition.hpp"
+#include <iostream>
+
+int main(int argc, char const *argv[]) {
+    long long n;
+    optimizeIO(), std::cin >> n;
+
+    auto res = sqrt_decomposit(n);
+    std::reverse(res.begin(), res.end());
+
+    std::cout << res.size() << '\n';
+    for (auto &[l, r, v] : res) {
+        std::cout << v << " ";
+    }
+    return 0;
+}