LeetCode Wildcard Matching

Problem

My solution is simple:

• Split the pattern into parts by *;
• Match the head and tail;
• Match the inside parts;

The challenge is the numerous corner cases.

public class Solution {
    public boolean isMatch(String s, String p) {
        if (s.isEmpty() && p.isEmpty()) {
            return true;
        } else if (p.isEmpty()) {
            return false;
        }
        boolean tail = p.charAt(p.length()-1) == '*';

        String[] ps = p.split("\\*");
        int pos = 0;
        for (int i = 0; i < ps.length; i++) {
            //Skip *
            if (ps[i].equals("")) {
                continue;
            }
            if (i == ps.length-1 && !tail) {
                //Match the tail if the tail is not *
                int newPos = s.length() - ps[i].length();
                if (newPos < pos || newPos >= s.length()) {
                    return false;
                }
                pos = isPartialMatch(s, newPos, ps[i]);
            } else {
                //Match inside parts
                pos = isPartialMatch(s, pos, ps[i]);
            }
            //If unmatched partially, return false;
            if (pos == -1) {
                return false;
            }
            //Not start with * and the head not matched, return false;
            if (i == 0 && pos > 0) {
                return false;
            }
            //March to next partial match
            pos += ps[i].length();
        }
        //If not end with * and the tail is not matched, return false;
        if (pos < s.length() && !tail) {
            return false;
        }
        return true;
    }

    public int isPartialMatch(String s, int i, String p) {
        if (i >= s.length()) {
            return -1;
        }
        int n = s.length() - p.length();
        int l = p.length();
        for(; i <= n; i++) {
            boolean flag = true;
            for (int j = 0; j < l; j++) {
                if (s.charAt(i+j) != p.charAt(j) && p.charAt(j) != '?') {
                    flag = false;
                    break;
                }
            }
            if (flag) {
                return i;
            }
        }
        return -1;
    }
}