leetcode---regular-expression-matching---字符串

Implement regular expression matching with support for’.’and’*’.

‘.’ Matches any single character.

‘*’ Matches zero or more of the preceding element.

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”, “a*”) → true

isMatch(“aa”, “.*”) → true

isMatch(“ab”, “.*”) → true

isMatch(“aab”, “c*a*b”) → true

class Solution {
public:
bool isMatch(const char *s, const char *p)
{
int n = strlen(s);
int m = strlen(p);
vector<vector<bool> > dp(n+1, vector<bool>(m+1, false));

dp[0][0] = true;

for(int i=0; i<=n; i++)
{
for(int j=1; j<=m; j++)
{
if(j>1 && p[j-1] == '*')
dp[i][j] = dp[i][j-2] || (i>0 && (s[i-1] == p[j-2] || p[j-2] == '.') && dp[i-1][j]);
else
dp[i][j] = i>0 && dp[i-1][j-1] && (s[i-1] == p[j-1] || p[j-1] == '.');
}
}

return dp
[m];
}
};