10.js

/** ------------------------------------------------------------------------------
 *
 * 10. Regular Expression Matching
 * Topics: String, Dynamic Programming, Recursion
 * https://leetcode.com/problems/regular-expression-matching/description/
 *
 ------------------------------------------------------------------------------ */
/**
 * @param {string} s
 * @param {string} p
 * @return {boolean}
 */
var isMatch = function (s, p) {
  const m = s.length
  const n = p.length
  const dp = Array.from({ length: m + 1 }, () => new Array(n + 1).fill(false))
  dp[0][0] = true

  for (let j = 2; j <= n; j++) {
    if (p[j - 1] === "*") dp[0][j] = dp[0][j - 2]
  }

  for (let i = 1; i <= m; i++) {
    for (let j = 1; j <= n; j++) {
      if (p[j - 1] === "." || p[j - 1] === s[i - 1]) {
        dp[i][j] = dp[i - 1][j - 1]
      } else if (p[j - 1] === "*") {
        dp[i][j] = dp[i][j - 2]
        if (p[j - 2] === "." || p[j - 2] === s[i - 1]) {
          dp[i][j] = dp[i][j] || dp[i - 1][j]
        }
      }
    }
  }

  return dp[m][n]
}

console.log(isMatch("aa", "a"))           // false
console.log(isMatch("aa", "a*"))          // true
console.log(isMatch("ab", ".*"))          // true
console.log(isMatch("aab", "c*a*b"))      // true
console.log(isMatch("mississippi", "mis*is*p*."))  // false
console.log(isMatch("", ""))              // true
console.log(isMatch("", "a*"))            // true