Add solution 228、1694、1695

leetcode/0228.Summary-Ranges/228. Summary Ranges.go

@@ -0,0 +1,19 @@
+package leetcode
+
+import (
+	"strconv"
+)
+
+func summaryRanges(nums []int) (ans []string) {
+	for i, n := 0, len(nums); i < n; {
+		left := i
+		for i++; i < n && nums[i-1]+1 == nums[i]; i++ {
+		}
+		s := strconv.Itoa(nums[left])
+		if left != i-1 {
+			s += "->" + strconv.Itoa(nums[i-1])
+		}
+		ans = append(ans, s)
+	}
+	return
+}

leetcode/0228.Summary-Ranges/228. Summary Ranges_test.go

@@ -0,0 +1,62 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question228 struct {
+	para228
+	ans228
+}
+
+// para 是参数
+// one 代表第一个参数
+type para228 struct {
+	nums []int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans228 struct {
+	ans []string
+}
+
+func Test_Problem228(t *testing.T) {
+
+	qs := []question228{
+
+		{
+			para228{[]int{0, 1, 2, 4, 5, 7}},
+			ans228{[]string{"0->2", "4->5", "7"}},
+		},
+
+		{
+			para228{[]int{0, 2, 3, 4, 6, 8, 9}},
+			ans228{[]string{"0", "2->4", "6", "8->9"}},
+		},
+
+		{
+			para228{[]int{}},
+			ans228{[]string{}},
+		},
+
+		{
+			para228{[]int{-1}},
+			ans228{[]string{"-1"}},
+		},
+
+		{
+			para228{[]int{0}},
+			ans228{[]string{"0"}},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 228------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans228, q.para228
+		fmt.Printf("【input】:%v       【output】:%v\n", p, summaryRanges(p.nums))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/0228.Summary-Ranges/README.md

@@ -0,0 +1,107 @@
+# [228. Summary Ranges](https://leetcode.com/problems/summary-ranges/)
+
+## 题目
+
+You are given a **sorted unique** integer array `nums`.
+
+Return *the **smallest sorted** list of ranges that **cover all the numbers in the array exactly***. That is, each element of `nums` is covered by exactly one of the ranges, and there is no integer `x` such that `x` is in one of the ranges but not in `nums`.
+
+Each range `[a,b]` in the list should be output as:
+
+- `"a->b"` if `a != b`
+- `"a"` if `a == b`
+
+**Example 1:**
+
+```
+Input: nums = [0,1,2,4,5,7]
+Output: ["0->2","4->5","7"]
+Explanation: The ranges are:
+[0,2] --> "0->2"
+[4,5] --> "4->5"
+[7,7] --> "7"
+
+```
+
+**Example 2:**
+
+```
+Input: nums = [0,2,3,4,6,8,9]
+Output: ["0","2->4","6","8->9"]
+Explanation: The ranges are:
+[0,0] --> "0"
+[2,4] --> "2->4"
+[6,6] --> "6"
+[8,9] --> "8->9"
+
+```
+
+**Example 3:**
+
+```
+Input: nums = []
+Output: []
+
+```
+
+**Example 4:**
+
+```
+Input: nums = [-1]
+Output: ["-1"]
+
+```
+
+**Example 5:**
+
+```
+Input: nums = [0]
+Output: ["0"]
+
+```
+
+**Constraints:**
+
+- `0 <= nums.length <= 20`
+- `231 <= nums[i] <= 231 - 1`
+- All the values of `nums` are **unique**.
+- `nums` is sorted in ascending order.
+
+## 题目大意
+
+给定一个无重复元素的有序整数数组 nums 。
+
+返回 恰好覆盖数组中所有数字 的 最小有序 区间范围列表。也就是说，nums 的每个元素都恰好被某个区间范围所覆盖，并且不存在属于某个范围但不属于 nums 的数字 x 。
+
+列表中的每个区间范围 [a,b] 应该按如下格式输出：
+
+- "a->b" ，如果 a != b
+- "a" ，如果 a == b
+
+## 解题思路
+
+- 简单题。按照题意，用一个游标变量累加寻找连续的区间。一旦出现了中断，就按照题意格式输出。输出的规则有多种，带箭头的区间，单个元素区间，空区间。
+
+## 代码
+
+```go
+package leetcode
+
+import (
+	"strconv"
+)
+
+func summaryRanges(nums []int) (ans []string) {
+	for i, n := 0, len(nums); i < n; {
+		left := i
+		for i++; i < n && nums[i-1]+1 == nums[i]; i++ {
+		}
+		s := strconv.Itoa(nums[left])
+		if left != i-1 {
+			s += "->" + strconv.Itoa(nums[i-1])
+		}
+		ans = append(ans, s)
+	}
+	return
+}
+```