# 44 Wildcard Matching

### Problem:

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", "c*a*b") → false
``````

### Solutions:

DP is the easy way to think. match[i][j] means for String s [0, i) using pattern p [0, j) if it's matchable. then match[i][j] = match[i-1][j-1] if p.charAt(j) == s.charAt(i) || p.charAt(j) == '?' match[i][j] = match[i-1][j] || match[i][j-1] if p.charAt(j) == '*'

But DP is not fast enough to solve this.

``````public class Solution {
public boolean isMatch(String s, String p) {
int i = 0;
int j = 0;
int starti = -1;
int startj = -1;
while (i < s.length()) {
if (j < p.length() && (p.charAt(j) == '?' || p.charAt(j) == s.charAt(i))) {
i ++;
j ++;
}
else if (j < p.length() && p.charAt(j) == '*') {
starti = i;
startj = j;
j ++;
}
else if (startj != -1) {
j = startj + 1;
i = starti + 1;
starti ++;
}
else {
return false;
}
}
while (j < p.length() && p.charAt(j) == '*') {
j ++;
}
return j == p.length();
}
}
``````
``````class Solution {
public boolean isMatch(String s, String p) {
boolean[][] dp = new boolean[s.length() + 1][p.length() + 1];
dp[0][0] = true;
for (int j = 1; j <= p.length(); j ++) {
if (p.charAt(j - 1) == '*') {
dp[0][j] = dp[0][j - 1];
}
}
for (int i = 1; i < s.length() + 1; i ++) {
for (int j = 1; j < p.length() + 1; j ++) {
if (p.charAt(j - 1) == '?' || p.charAt(j - 1) == s.charAt(i - 1)) {
dp[i][j] = dp[i][j] || dp[i - 1][j - 1];
}
else if (p.charAt(j - 1) == '*') {
dp[i][j] = dp[i - 1][j] || dp[i][j - 1];
}
}
}

return dp[s.length()][p.length()];
}
}
``````