题目
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
分析
通过率很低的一题,Java没指针写起来是不顺畅。
贪心的策略,能匹配就一直往后遍历,匹配不上了就看看前面有没有'*'来救救场,再从'*'后面接着试。
代码
public class WildcardMatching {
public boolean isMatch(String s, String p) {
int i = 0;
int j = 0;
int star = -1;
int mark = -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) == '*') {
star = j++;
mark = i;
} else if (star != -1) {
j = star + 1;
i = ++mark;
} else {
return false;
}
}
while (j < p.length() && p.charAt(j) == '*') {
++j;
}
return j == p.length();
}
}