Word Break

class Solution {
public:
    bool wordBreak(string s, vector<string>& wordDict) {
        unordered_set<string> dict(wordDict.begin(), wordDict.end());
        int n = s.size();
        vector<bool> dp(n + 1, false);
        dp[0] = true;
        for (int i = 1; i <= n; ++i) {
            for (int j = i - 1; j >= 0; --j) {
                if (dp[j] && dict.count(s.substr(j, i - j))) { dp[i] = true; break; }
            }
        }
        return dp[n];
    }
};

func wordBreak(s string, wordDict []string) bool {
    dict := map[string]bool{}
    for _, w := range wordDict {
        dict[w] = true
    }
    n := len(s)
    dp := make([]bool, n+1)
    dp[0] = true
    for i := 1; i <= n; i++ {
        for j := i - 1; j >= 0; j-- {
            if dp[j] && dict[s[j:i]] {
                dp[i] = true
                break
            }
        }
    }
    return dp[n]
}

from typing import List

class Solution:
    def wordBreak(self, s: str, wordDict: List[str]) -> bool:
        dict_set = set(wordDict)
        n = len(s)
        dp = [False] * (n + 1)
        dp[0] = True
        for i in range(1, n + 1):
            for j in range(i - 1, -1, -1):
                if dp[j] and s[j:i] in dict_set:
                    dp[i] = True
                    break
        return dp[n]

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

class Solution {
    public boolean wordBreak(String s, List<String> wordDict) {
        Set<String> dict = new HashSet<>(wordDict);
        int n = s.length();
        boolean[] dp = new boolean[n + 1];
        dp[0] = true;
        for (int i = 1; i <= n; i++) {
            for (int j = i - 1; j >= 0; j--) {
                if (dp[j] && dict.contains(s.substring(j, i))) {
                    dp[i] = true;
                    break;
                }
            }
        }
        return dp[n];
    }
}

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