题目描述(Hard)
Given an input string (s) and a pattern (p), 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).
Note:
- s could be empty and contains only lowercase letters a-z.
- p could be empty and contains only lowercase letters a-z, and characters like ? or *.
题目链接
https://leetcode.com/problems/wildcard-matching/description/
Example 1:
Input:
s = "aa"
p = "a"
Output: false
Explanation: "a" does not match the entire string "aa".
Example 2:
Input:
s = "aa"
p = "*"
Output: true
Explanation: '*' matches any sequence.
Example 3:
Input:
s = "cb"
p = "?a"
Output: false
Explanation: '?' matches 'c', but the second letter is 'a', which does not match 'b'.
Example 4:
Input:
s = "adceb"
p = "*a*b"
Output: true
Explanation: The first '*' matches the empty sequence, while the second '*' matches the substring "dce".
Example 5:
Input:
s = "acdcb"
p = "a*c?b"
Output: false
算法分析
回溯法，每当遇到'*'时，就保留当前的'*'的坐标(下一位作为回溯位)和s的坐标，然后s从前往后扫描，如果不成功，则回溯，并且回溯位后移++s，重新扫描，时间复杂度
提交代码：
class Solution {
public:
bool isMatch(string s, string p) {
return isMatchCore(s.c_str(), p.c_str());
}
bool isMatchCore(const char *s, const char *p)
{
bool star = false;
const char *str, *ptr;
for (str = s, ptr = p; *str != '\0'; ++str, ++ptr)
{
if (*ptr == '?') continue;
else if (*ptr == '*')
{
star = true;
p = ptr, s = str;
while (*p == '*') ++p;
if (*p == '\0') return true;
ptr = p - 1;
str = s - 1;
}
else
{
if (*ptr != *str)
{
if (!star) return false;
++s;
ptr = p - 1;
str = s - 1;
}
}
}
while (*ptr == '*') ++ptr;
return (*ptr == '\0');
}
};测试代码：
// ====================测试代码====================
void Test(const char* testName, string str, string p, bool expected)
{
if (testName != nullptr)
printf("%s begins: \n", testName);
Solution s;
bool result = s.isMatch(str, p);
if(result == expected)
printf("passed\n");
else
printf("failed\n");
}
int main(int argc, char* argv[])
{
Test("Test1", string("aa"), string("a"), false);
Test("Test2", string("aa"), string("*"), true);
Test("Test3", string("cb"), string("?a"), false);
Test("Test4", string("adceb"), string("*a*b"), true);
Test("Test5", string("acdcb"), string("a*c?b"), false);
return 0;
}