Add solution 1668、1669、1670、1672、1673

leetcode/1668.Maximum-Repeating-Substring/README.md

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+# [1668. Maximum Repeating Substring](https://leetcode.com/problems/maximum-repeating-substring/)
+
+
+## 题目
+
+For a string `sequence`, a string `word` is **`k`-repeating** if `word` concatenated `k` times is a substring of `sequence`. The `word`'s **maximum `k`-repeating value** is the highest value `k` where `word` is `k`-repeating in `sequence`. If `word` is not a substring of `sequence`, `word`'s maximum `k`-repeating value is `0`.
+
+Given strings `sequence` and `word`, return *the **maximum `k`-repeating value** of `word` in `sequence`*.
+
+**Example 1:**
+
+```
+Input: sequence = "ababc", word = "ab"
+Output: 2
+Explanation: "abab" is a substring in "ababc".
+```
+
+**Example 2:**
+
+```
+Input: sequence = "ababc", word = "ba"
+Output: 1
+Explanation: "ba" is a substring in "ababc". "baba" is not a substring in "ababc".
+```
+
+**Example 3:**
+
+```
+Input: sequence = "ababc", word = "ac"
+Output: 0
+Explanation: "ac" is not a substring in "ababc". 
+```
+
+**Constraints:**
+
+- `1 <= sequence.length <= 100`
+- `1 <= word.length <= 100`
+- `sequence` and `word` contains only lowercase English letters.
+
+## 题目大意
+
+给你一个字符串 sequence ，如果字符串 word 连续重复 k 次形成的字符串是 sequence 的一个子字符串，那么单词 word 的 重复值为 k 。单词 word 的 最大重复值 是单词 word 在 sequence 中最大的重复值。如果 word 不是 sequence 的子串，那么重复值 k 为 0 。给你一个字符串 sequence 和 word ，请你返回 最大重复值 k 。
+
+## 解题思路
+
+- 循环叠加构造 `word`，每次构造出新的 `word` 都在 `sequence` 查找一次，如果找到就输出叠加次数，否则继续叠加构造，直到字符串长度和 `sequence` 一样长，最终都没有找到则输出 0 。
+
+## 代码
+
+```go
+package leetcode
+
+import (
+	"strings"
+)
+
+func maxRepeating(sequence string, word string) int {
+	for i := len(sequence) / len(word); i >= 0; i-- {
+		tmp := ""
+		for j := 0; j < i; j++ {
+			tmp += word
+		}
+		if strings.Contains(sequence, tmp) {
+			return i
+		}
+	}
+	return 0
+}
+```