Merge pull request 6boris#587 from 0xff-dev/1237

Add solution and test-cases for problem 1237

Author: 6boris

leetcode/1201-1300/1237.Find-Positive-Integer-Solution-for-a-Given-Equation/README.md

@@ -1,28 +1,53 @@
 # [1237.Find Positive Integer Solution for a Given Equation][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+Given a callable function `f(x, y)` **with a hidden formula** and a value `z`, reverse engineer the formula and return all positive integer pairs `x` and y where `f(x,y) == z`. You may return the pairs in any order.
 
-**Example 1:**
+While the exact formula is hidden, the function is monotonically increasing, i.e.:
+
+- `f(x, y) < f(x + 1, y)`
+- `f(x, y) < f(x, y + 1)`
+
+The function interface is defined like this:
 
 ```
-Input: a = "11", b = "1"
-Output: "100"
+interface CustomFunction {
+public:
+  // Returns some positive integer f(x, y) for two positive integers x and y based on a formula.
+  int f(int x, int y);
+};
 ```
 
-## 题意
-> ...
+We will judge your solution as follows:
+
+- The judge has a list of `9` hidden implementations of `CustomFunction`, along with a way to generate an **answer key** of all valid pairs for a specific `z`.
+- The judge will receive two inputs: a `function_id` (to determine which implementation to test your code with), and the target `z`.
+- The judge will call your `findSolution` and compare your results with the **answer key**.
+- If your results match the **answer key**, your solution will be `Accepted`.
 
-## 题解
+**Example 1:**
 
-### 思路1
-> ...
-Find Positive Integer Solution for a Given Equation
-```go
 ```
+Input: function_id = 1, z = 5
+Output: [[1,4],[2,3],[3,2],[4,1]]
+Explanation: The hidden formula for function_id = 1 is f(x, y) = x + y.
+The following positive integer values of x and y make f(x, y) equal to 5:
+x=1, y=4 -> f(1, 4) = 1 + 4 = 5.
+x=2, y=3 -> f(2, 3) = 2 + 3 = 5.
+x=3, y=2 -> f(3, 2) = 3 + 2 = 5.
+x=4, y=1 -> f(4, 1) = 4 + 1 = 5.
+```
+
+**Example 2:**
 
+```
+Input: function_id = 2, z = 5
+Output: [[1,5],[5,1]]
+Explanation: The hidden formula for function_id = 2 is f(x, y) = x * y.
+The following positive integer values of x and y make f(x, y) equal to 5:
+x=1, y=5 -> f(1, 5) = 1 * 5 = 5.
+x=5, y=1 -> f(5, 1) = 5 * 1 = 5.
+```
 
 ## 结语
 

leetcode/1201-1300/1237.Find-Positive-Integer-Solution-for-a-Given-Equation/Solution.go

@@ -1,5 +1,26 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+func Solution(customFunction func(int, int) int, z int) [][]int {
+	ans := make([][]int, 0)
+	for y := 1; y <= 1000; y++ {
+		l, r := 1, 1000
+		if r := customFunction(1, y); r > z {
+			break
+		}
+		for l < r {
+			m := l + (r-l)/2
+			rr := customFunction(m, y)
+
+			if rr == z {
+				ans = append(ans, []int{m, y})
+				break
+			}
+			if rr < z {
+				l = m + 1
+				continue
+			}
+			r = m
+		}
+	}
+	return ans
 }

leetcode/1201-1300/1237.Find-Positive-Integer-Solution-for-a-Given-Equation/Solution_test.go

@@ -6,34 +6,45 @@ import (
 	"testing"
 )
 
+func f1(a, b int) int {
+	return a + b
+}
+func f2(a, b int) int {
+	return a * b
+}
 func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		inputs func(int, int) int
+		z      int
+		expect [][]int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", f1, 5, [][]int{{4, 1}, {3, 2}, {2, 3}, {1, 4}}},
+		{"TestCase2", f2, 480, [][]int{
+			{480, 1}, {240, 2}, {160, 3}, {120, 4}, {96, 5}, {80, 6}, {60, 8}, {48, 10},
+			{40, 12}, {32, 15}, {30, 16}, {24, 20}, {20, 24}, {16, 30}, {15, 32},
+			{12, 40}, {10, 48}, {8, 60}, {6, 80}, {5, 96}, {4, 120}, {3, 160}, {2, 240}, {1, 480},
+		}},
+		{"TestCase3", f2, 5, [][]int{{5, 1}, {1, 5}}},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.inputs, c.z)
 			if !reflect.DeepEqual(got, c.expect) {
 				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+					c.expect, got, c.z)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }