LeetCode Word Pattern

Given a

pattern

and a string

str

, find if

str

follows the same pattern.

Here follow means a full match, such that there is a bijection between a letter in

pattern

and a non-empty word in

str

.

Examples:

pattern =

"abba"

, str =

"dog cat cat dog"

should return true.

pattern =

"abba"

, str =

"dog cat cat fish"

should return false.

pattern =

"aaaa"

, str =

"dog cat cat dog"

should return false.

pattern =

"abba"

, str =

"dog dog dog dog"

should return false.

Notes:
You may assume

pattern

contains only lowercase letters, and

str

contains lowercase letters separated by a single space.

题目的大致意思是：给两个字符串，其中一个表示轨迹，检查第二个字符串是否符合第一个轨迹而存在，如果两者轨迹相同返回true，不同则返回false。 其中注意:pattern="aaaa",str="aa aa aa aa aa aa"两者轨迹并不相同

class Solution {
public:
bool wordPattern(string pattern, string str) {
auto beg = begin(str), en = end(str);
string::iterator mid=beg;
map<char, string> ma;
for (unsigned i = 0;i < pattern.size();++i)
{
for (;mid != en && ((*mid) != ' ');++mid);
if(ma.find(pattern[i])==ma.end())
ma[pattern[i]] = string(beg, mid);
if (ma.find(pattern[i]) != ma.end() && ma[pattern[i]] != string(beg, mid))
return false;
if(mid!=en)
beg = ++mid;
}
map<string, char> test;
for (auto e : ma)
test[e.second] = e.first;
if (ma.size( )!= test.size()||mid!=en)
return false;
return true;
}
};