Perfect squares

leetcode-cc/PerfectSquares.hpp

@@ -0,0 +1,53 @@
+#include <queue>
+#include <unordered_set>
+
+#include "TestHelper.h"
+#include "problem.h"
+#include "solution.h"
+
+using namespace std;
+
+IMPLEMENT_PROBLEM_CLASS(PPerfectSquares, 279, DIFFI_MEDIUM, TOPIC_ALGORITHMS,
+                        "Perfect Squares",
+                        "Given an integer n, return the least number of "
+                        "perfect square numbers that sum to n.",
+                        {"Math"});
+
+class SPerfectSquares : public ISolution {
+ public:
+  size_t problemId() const override { return 279; }
+  string name() const override {
+    return ("Solution for " + string("Perfect Squares"));
+  }
+  string location() const override { return __FILE_NAME__; }
+  int test() const override {
+    return testHelper<int, int>({12, 13}, {3, 2}, [this](auto input) {
+      return this->numSquares(input);
+    });
+  };
+  int benchmark() const override { return 0; }
+
+ private:
+  int numSquares(int n) const {
+    queue<pair<int, int>> q = {};
+    unordered_set<int> memo = {};
+
+    q.push({0, 0});
+
+    while (!q.empty()) {
+      auto [val, step] = q.front();
+      q.pop();
+
+      if (val == n) return step;
+
+      memo.insert({val, step});
+
+      for (int i = 1; i * i + val <= n; i++) {
+        auto nextVal = val + i * i;
+        if (!memo.contains(nextVal)) q.push({nextVal, step + 1});
+      }
+    }
+
+    return -1;
+  }
+};

runtime-cc/src/registration.cc

@@ -94,6 +94,7 @@
 #include "../leetcode-cc/PascalsTriangleII.hpp"
 #include "../leetcode-cc/PathSum.hpp"
 #include "../leetcode-cc/PathSumII.hpp"
+#include "../leetcode-cc/PerfectSquares.hpp"
 #include "../leetcode-cc/PopulateNextRightPointers.hpp"
 #include "../leetcode-cc/ProductOfArrayExceptSelf.hpp"
 #include "../leetcode-cc/PseudoPalindromicPathsInBTree.hpp"
@@ -982,5 +983,10 @@ const int registerAll(std::shared_ptr<Container> handle) {
     return std::make_shared<SProductOfArrayExceptSelf>();
   });
 
+  handle->registerProblem(
+      []() -> ArcProblem { return std::make_shared<PPerfectSquares>(); });
+  handle->registerSolution(
+      []() -> ArcSolution { return std::make_shared<SPerfectSquares>(); });
+
   return 0;
 }