[Leetcode] Word Break

Given a string s and a dictionary of words dict, determine if s can be segmented into a space-separated sequence of one or more dictionary words.

For example, given
s = "leetcode",
dict = ["leet", "code"].

Return true because "leetcode" can be segmented as "leet code".

DP problem. We use dp[i] to indicate wether s[0...i] could be split by the dict or not. Then only when we find some position j that dp[j-1] == true and s[j...i] is contained in the dict, dp[i] = true. Be careful when j = 0.

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