js版Leetcode第一难题wildcard-matching

问题

原题地址： https://leetcode.com/problems/wildcard-matching/

Implement wildcard pattern matching with support for '?' and '*'.

'?' Matches any single character.

'*' Matches any sequence of characters (including the empty sequence).

The matching should cover the entire input string (not partial).

The function prototype should be:

bool isMatch(const char *s, const char *p)

Some examples:

isMatch("aa","a") → false

isMatch("aa","aa") → true

isMatch("aaa","aa") → false

isMatch("aa", "*") → true

isMatch("aa", "a*") → true

isMatch("ab", "?*") → true

isMatch("aab", "cab") → false

Timeout 版结果

//Timeout Version:
var isMatch = function (s, p) {
  p = p.replace(/\?/g, '.').replace(/\*+/g, '.*');
  var reg = new RegExp('^' + p + '$');
  return reg.test(s);
};

正则表达式的效率还是很低的.

JS 版通过结果

/**
 * @param {string} str
 * @param {string} pattern
 * @return {boolean}
 */
var isMatch = function (str, pattern) {
  var s = 0,
    p = 0,
    match = 0,
    index = -1;
  while (s < str.length) {
    if (p < pattern.length && (pattern.charAt(p) == '?' || str.charAt(s) === pattern.charAt(p))) {
      s++;
      p++;
    } else if (p < pattern.length && pattern.charAt(p) === '*') {
      index = p;
      match = s;
      p++;
    } else if (index != -1) {
      p = index + 1;
      match++;
      s = match;
    } else {
      return false;
    }
  }
  while (p < pattern.length && pattern.charAt(p) === '*') {
    p++;
  }
  return p === pattern.length;
};