Add Weekly Contest 218

Author: halfrost

leetcode/5617.Goal-Parser-Interpretation/5617. Goal Parser Interpretation.go renamed to leetcode/1678.Goal-Parser-Interpretation/1678. Goal Parser Interpretation.go

@@ -14,7 +14,7 @@ func interpret(command string) string {
 				i += 3
 			} else {
 				res += "o"
-				i += 1
+				i++
 			}
 		}
 	}

leetcode/1678.Goal-Parser-Interpretation/1678. Goal Parser Interpretation_test.go

@@ -0,0 +1,52 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question1678 struct {
+	para1678
+	ans1678
+}
+
+// para 是参数
+// one 代表第一个参数
+type para1678 struct {
+	command string
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans1678 struct {
+	one string
+}
+
+func Test_Problem1678(t *testing.T) {
+
+	qs := []question1678{
+
+		{
+			para1678{"G()(al)"},
+			ans1678{"Goal"},
+		},
+
+		{
+			para1678{"G()()()()(al)"},
+			ans1678{"Gooooal"},
+		},
+
+		{
+			para1678{"(al)G(al)()()G"},
+			ans1678{"alGalooG"},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 1678------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans1678, q.para1678
+		fmt.Printf("【input】:%v       【output】:%v\n", p, interpret(p.command))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/1678.Goal-Parser-Interpretation/README.md

@@ -0,0 +1,73 @@
+# [1678. Goal Parser Interpretation](https://leetcode.com/problems/goal-parser-interpretation/)
+
+## 题目
+
+You own a **Goal Parser** that can interpret a string `command`. The `command` consists of an alphabet of `"G"`, `"()"` and/or `"(al)"` in some order. The Goal Parser will interpret `"G"` as the string `"G"`, `"()"` as the string `"o"`, and `"(al)"` as the string `"al"`. The interpreted strings are then concatenated in the original order.
+
+Given the string `command`, return *the **Goal Parser**'s interpretation of* `command`.
+
+**Example 1:**
+
+```
+Input: command = "G()(al)"
+Output: "Goal"
+Explanation: The Goal Parser interprets the command as follows:
+G -> G
+() -> o
+(al) -> al
+The final concatenated result is "Goal".
+```
+
+**Example 2:**
+
+```
+Input: command = "G()()()()(al)"
+Output: "Gooooal"
+```
+
+**Example 3:**
+
+```
+Input: command = "(al)G(al)()()G"
+Output: "alGalooG"
+```
+
+**Constraints:**
+
+- `1 <= command.length <= 100`
+- `command` consists of `"G"`, `"()"`, and/or `"(al)"` in some order.
+
+## 题目大意
+
+请你设计一个可以解释字符串 command 的 Goal 解析器 。command 由 "G"、"()" 和/或 "(al)" 按某种顺序组成。Goal 解析器会将 "G" 解释为字符串 "G"、"()" 解释为字符串 "o" ，"(al)" 解释为字符串 "al" 。然后，按原顺序将经解释得到的字符串连接成一个字符串。给你字符串 command ，返回 Goal 解析器 对 command 的解释结果。
+
+## 解题思路
+
+- 简单题，按照题意修改字符串即可。由于是简单题，这一题也不用考虑嵌套的情况。
+
+## 代码
+
+```go
+package leetcode
+
+func interpret(command string) string {
+	if command == "" {
+		return ""
+	}
+	res := ""
+	for i := 0; i < len(command); i++ {
+		if command[i] == 'G' {
+			res += "G"
+		} else {
+			if command[i] == '(' && command[i+1] == 'a' {
+				res += "al"
+				i += 3
+			} else {
+				res += "o"
+				i ++
+			}
+		}
+	}
+	return res
+}
+```

leetcode/1679.Max-Number-of-K-Sum-Pairs/1679. Max Number of K-Sum Pairs.go

@@ -0,0 +1,48 @@
+package leetcode
+
+// 解法一 优化版
+func maxOperations(nums []int, k int) int {
+	counter, res := make(map[int]int), 0
+	for _, n := range nums {
+		counter[n]++
+	}
+	if (k & 1) == 0 {
+		res += counter[k>>1] >> 1
+		// 能够由 2 个相同的数构成 k 的组合已经都排除出去了，剩下的一个单独的也不能组成 k 了
+		// 所以这里要把它的频次置为 0 。如果这里不置为 0，下面代码判断逻辑还需要考虑重复使用数字的情况
+		counter[k>>1] = 0
+	}
+	for num, freq := range counter {
+		if num <= k/2 {
+			remain := k - num
+			if counter[remain] < freq {
+				res += counter[remain]
+			} else {
+				res += freq
+			}
+		}
+	}
+	return res
+}
+
+// 解法二
+func maxOperations_(nums []int, k int) int {
+	counter, res := make(map[int]int), 0
+	for _, num := range nums {
+		counter[num]++
+		remain := k - num
+		if num == remain {
+			if counter[num] >= 2 {
+				res++
+				counter[num] -= 2
+			}
+		} else {
+			if counter[remain] > 0 {
+				res++
+				counter[remain]--
+				counter[num]--
+			}
+		}
+	}
+	return res
+}

leetcode/1679.Max-Number-of-K-Sum-Pairs/1679. Max Number of K-Sum Pairs_test.go

@@ -0,0 +1,58 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question1679 struct {
+	para1679
+	ans1679
+}
+
+// para 是参数
+// one 代表第一个参数
+type para1679 struct {
+	nums []int
+	k    int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans1679 struct {
+	one int
+}
+
+func Test_Problem1679(t *testing.T) {
+
+	qs := []question1679{
+
+		{
+			para1679{[]int{1, 2, 3, 4}, 5},
+			ans1679{2},
+		},
+
+		{
+			para1679{[]int{3, 1, 3, 4, 3}, 6},
+			ans1679{1},
+		},
+
+		{
+			para1679{[]int{2, 5, 4, 4, 1, 3, 4, 4, 1, 4, 4, 1, 2, 1, 2, 2, 3, 2, 4, 2}, 3},
+			ans1679{4},
+		},
+
+		{
+			para1679{[]int{2, 5, 5, 5, 1, 3, 4, 4, 1, 4, 4, 1, 3, 1, 3, 1, 3, 2, 4, 2}, 6},
+			ans1679{8},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 1679------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans1679, q.para1679
+		fmt.Printf("【input】:%v       【output】:%v\n", p, maxOperations(p.nums, p.k))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/1679.Max-Number-of-K-Sum-Pairs/README.md

@@ -0,0 +1,98 @@
+# [1679. Max Number of K-Sum Pairs](https://leetcode.com/problems/max-number-of-k-sum-pairs/)
+
+
+## 题目
+
+You are given an integer array `nums` and an integer `k`.
+
+In one operation, you can pick two numbers from the array whose sum equals `k` and remove them from the array.
+
+Return *the maximum number of operations you can perform on the array*.
+
+**Example 1:**
+
+```
+Input: nums = [1,2,3,4], k = 5
+Output: 2
+Explanation: Starting with nums = [1,2,3,4]:
+- Remove numbers 1 and 4, then nums = [2,3]
+- Remove numbers 2 and 3, then nums = []
+There are no more pairs that sum up to 5, hence a total of 2 operations.
+```
+
+**Example 2:**
+
+```
+Input: nums = [3,1,3,4,3], k = 6
+Output: 1
+Explanation: Starting with nums = [3,1,3,4,3]:
+- Remove the first two 3's, then nums = [1,4,3]
+There are no more pairs that sum up to 6, hence a total of 1 operation.
+```
+
+**Constraints:**
+
+- `1 <= nums.length <= 105`
+- `1 <= nums[i] <= 109`
+- `1 <= k <= 109`
+
+## 题目大意
+
+给你一个整数数组 nums 和一个整数 k 。每一步操作中，你需要从数组中选出和为 k 的两个整数，并将它们移出数组。返回你可以对数组执行的最大操作数。
+
+## 解题思路
+
+- 读完题第一感觉这道题是 TWO SUM 题目的加强版。需要找到所有满足和是 k 的数对。先考虑能不能找到两个数都是 k/2 ，如果能找到多个这样的数，可以先移除他们。其次在利用 TWO SUM 的思路，找出和为 k 的数对。利用 TWO SUM 里面 map 的做法，时间复杂度 O(n)。
+
+## 代码
+
+```go
+package leetcode
+
+// 解法一 优化版
+func maxOperations(nums []int, k int) int {
+	counter, res := make(map[int]int), 0
+	for _, n := range nums {
+		counter[n]++
+	}
+	if (k & 1) == 0 {
+		res += counter[k>>1] >> 1
+		// 能够由 2 个相同的数构成 k 的组合已经都排除出去了，剩下的一个单独的也不能组成 k 了
+		// 所以这里要把它的频次置为 0 。如果这里不置为 0，下面代码判断逻辑还需要考虑重复使用数字的情况
+		counter[k>>1] = 0
+	}
+	for num, freq := range counter {
+		if num <= k/2 {
+			remain := k - num
+			if counter[remain] < freq {
+				res += counter[remain]
+			} else {
+				res += freq
+			}
+		}
+	}
+	return res
+}
+
+// 解法二
+func maxOperations_(nums []int, k int) int {
+	counter, res := make(map[int]int), 0
+	for _, num := range nums {
+		counter[num]++
+		remain := k - num
+		if num == remain {
+			if counter[num] >= 2 {
+				res++
+				counter[num] -= 2
+			}
+		} else {
+			if counter[remain] > 0 {
+				res++
+				counter[remain]--
+				counter[num]--
+			}
+		}
+	}
+	return res
+}
+```

leetcode/1680.Concatenation-of-Consecutive-Binary-Numbers/1680. Concatenation of Consecutive Binary Numbers.go

@@ -0,0 +1,26 @@
+package leetcode
+
+import (
+	"math/bits"
+)
+
+// 解法一 模拟
+func concatenatedBinary(n int) int {
+	res, mod, shift := 0, 1000000007, 0
+	for i := 1; i <= n; i++ {
+		if (i & (i - 1)) == 0 {
+			shift++
+		}
+		res = ((res << shift) + i) % mod
+	}
+	return res
+}
+
+// 解法二 位运算
+func concatenatedBinary1(n int) int {
+	res := 0
+	for i := 1; i <= n; i++ {
+		res = (res<<bits.Len(uint(i)) | i) % (1e9 + 7)
+	}
+	return res
+}