Merge pull request #1028 from 0xff-dev/2601

Add solution and test-cases for problem 2601

Author: 6boris

leetcode/2601-2700/2601.Prime-Subtraction-Operation/README.md

@@ -0,0 +1,45 @@
+# [2601.Prime Subtraction Operation][title]
+
+## Description
+You are given a **0-indexed** integer array `nums` of length `n`.
+
+You can perform the following operation as many times as you want:
+
+- Pick an index `i` that you haven’t picked before, and pick a prime `p` **strictly less than** `nums[i]`, then subtract `p` from `nums[i]`.
+
+Return true if you can make `nums` a strictly increasing array using the above operation and false otherwise.
+
+A **strictly increasing array** is an array whose each element is strictly greater than its preceding element.
+
+**Example 1:**
+
+```
+Input: nums = [4,9,6,10]
+Output: true
+Explanation: In the first operation: Pick i = 0 and p = 3, and then subtract 3 from nums[0], so that nums becomes [1,9,6,10].
+In the second operation: i = 1, p = 7, subtract 7 from nums[1], so nums becomes equal to [1,2,6,10].
+After the second operation, nums is sorted in strictly increasing order, so the answer is true.
+```
+
+**Example 2:**
+
+```
+Input: nums = [6,8,11,12]
+Output: true
+Explanation: Initially nums is sorted in strictly increasing order, so we don't need to make any operations.
+```
+
+**Example 3:**
+
+```
+Input: nums = [5,8,3]
+Output: false
+Explanation: It can be proven that there is no way to perform operations to make nums sorted in strictly increasing order, so the answer is false.
+```
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-algorithm][me]
+
+[title]: https://leetcode.com/problems/prime-subtraction-operation
+[me]: https://github.com/kylesliu/awesome-golang-algorithm

leetcode/2601-2700/2601.Prime-Subtraction-Operation/Solution.go

@@ -1,5 +1,38 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "math"
+
+func checkPrime(x int) bool {
+	for i := 2; i <= int(math.Sqrt(float64(x))); i++ {
+		if x%i == 0 {
+			return false
+		}
+	}
+	return true
+}
+
+func Solution(nums []int) bool {
+	for i := 0; i < len(nums); i++ {
+		var bound int
+		if i == 0 {
+			bound = nums[0]
+		} else {
+			bound = nums[i] - nums[i-1]
+		}
+
+		if bound <= 0 {
+			return false
+		}
+
+		largestPrime := 0
+		for j := bound - 1; j >= 2; j-- {
+			if checkPrime(j) {
+				largestPrime = j
+				break
+			}
+		}
+
+		nums[i] = nums[i] - largestPrime
+	}
+	return true
 }

leetcode/2601-2700/2601.Prime-Subtraction-Operation/Solution_test.go

@@ -10,12 +10,12 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
+		inputs []int
 		expect bool
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", []int{4, 9, 6, 10}, true},
+		{"TestCase2", []int{6, 8, 11, 12}, true},
+		{"TestCase3", []int{5, 8, 3}, false},
 	}
 
 	//	开始测试
@@ -30,10 +30,10 @@ func TestSolution(t *testing.T) {
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }