const wordBreak = function(s, wordDict){
 const wordDictSet = new Set(wordDict)
 const len = s.length
 const dp = new Array(len + 1).fill(false)
 dp[0] = true
 for (let i = 1; i <= len; i++) {
 for (let j = i - 1; j >= 0; j--) {
 const suffix = s.slice(j, i)
 if (wordDictSet.has(suffix) && dp[j]) {
 dp[i] = true
 break
 }
 }
 }
 return dp[len]
}