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24 lines
1.0 KiB
24 lines
1.0 KiB
package q10;
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/**
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* 回溯法 对于*字符，可以直接忽略模式串中这一部分，或者删除匹配串的第一个字符，前提是它能够匹配模式串当前位置字符，即 pattern[0]。如果两种操作中有任何一种使得剩下的字符串能匹配，那么初始时，匹配串和模式串就可以被匹配。
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*/
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public class Solution {
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public boolean isMatch(String text, String pattern) {
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if (pattern.isEmpty()) return text.isEmpty();
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boolean firstMatch = (!text.isEmpty() &&
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(pattern.charAt(0) == text.charAt(0) || pattern.charAt(0) == '.'));
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if (pattern.length() >= 2 && pattern.charAt(1) == '*') {
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return (isMatch(text, pattern.substring(2)) ||
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(firstMatch && isMatch(text.substring(1), pattern)));
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} else {
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return firstMatch && isMatch(text.substring(1), pattern.substring(1));
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}
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}
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public static void main(String[] args) {
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System.out.println(new Solution().isMatch("aaa", "a*a"));
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}
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}
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