[LeetCode]Wildcard Matching

标签：java   leetcode   回溯   

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

sIdx记录在s的位置，pIdx记录在p的位置，match记录在s中查询匹配的开始位置，starIdx记录了上一个*的具体位置，使用回溯的思想。

public class Solution {
    public boolean isMatch(String s, String p) {
        int sIdx = 0,pIdx = 0,starIdx = -1,match = 0;
        while(sIdx<s.length()){
        	if(pIdx<p.length()&&p.charAt(pIdx)=='*'){
        		starIdx = pIdx;
        		match = sIdx;
        		pIdx++;
        	}else if(pIdx<p.length()&&(p.charAt(pIdx)=='?'||p.charAt(pIdx)==s.charAt(sIdx))){
        		sIdx++;
        		pIdx++;
        	}else if(starIdx != -1){
        		pIdx = starIdx+1;
        		sIdx = ++match;
        	}else{
        		return false;
        	}
        }
        while(pIdx<p.length()&&p.charAt(pIdx)=='*'){
        	pIdx++;
        }
        if(pIdx==p.length()) return true;
        return false;
    }
}

[LeetCode]Wildcard Matching

标签：java   leetcode   回溯   

原文地址：http://blog.csdn.net/guorudi/article/details/42642953