leetcode/solution/0200-0299/0291.Word Pattern II/Solution.java

class Solution {
    private Set<String> vis;
    private Map<Character, String> d;
    private String p;
    private String s;
    private int m;
    private int n;

    public boolean wordPatternMatch(String pattern, String s) {
        vis = new HashSet<>();
        d = new HashMap<>();
        this.p = pattern;
        this.s = s;
        m = p.length();
        n = s.length();
        return dfs(0, 0);
    }

    private boolean dfs(int i, int j) {
        if (i == m && j == n) {
            return true;
        }
        if (i == m || j == n || m - i > n - j) {
            return false;
        }
        char c = p.charAt(i);
        for (int k = j + 1; k <= n; ++k) {
            String t = s.substring(j, k);
            if (d.getOrDefault(c, "").equals(t)) {
                if (dfs(i + 1, k)) {
                    return true;
                }
            }
            if (!d.containsKey(c) && !vis.contains(t)) {
                d.put(c, t);
                vis.add(t);
                if (dfs(i + 1, k)) {
                    return true;
                }
                vis.remove(t);
                d.remove(c);
            }
        }
        return false;
    }
}