Given a string s and a list of strings wordDict, return true if s can be split into a sequence of one or more dictionary words (each word may be reused any number of times).
dp[i] means "the first i characters of s can be fully segmented" — it's true if some earlier dp[j] is true and s[j:i] is in the dictionary.
Example
Input: s = "leetcode", wordDict = ["leet", "code"]
Output: true