87. Scramble String
Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.
Below is one possible representation of s1 = "great"
:
great / \ gr eat / \ / \ g r e at / \ a t
To scramble the string, we may choose any non-leaf node and swap its two children.
For example, if we choose the node "gr"
and
swap its two children, it produces a scrambled string "rgeat"
.
rgeat / \ rg eat / \ / \ r g e at / \ a t
We say that "rgeat"
is a scrambled
string of "great"
.
Similarly, if we continue to swap the children of nodes "eat"
and "at"
,
it produces a scrambled string "rgtae"
.
rgtae / \ rg tae / \ / \ r g ta e / \ t a
We say that "rgtae"
is a scrambled
string of "great"
.
Given two strings s1 and s2 of the same length, determine if s2 is a scrambled string of s1.
有一点递归的感觉。
class Solution {
public:
bool iscontain(string s1,string s2)
{
sort(s1.begin(), s1.end());
sort(s2.begin(), s2.end());
return (s1 == s2);
}
bool ischeck(string s1,string s2)//第i个的前面分割,s2作为target
{
if (s1 == s2)
return 1;
if ( !iscontain(s1, s2))
return 0;
int tsize = s2.size();
for (int i = 1; i < tsize; i++)
{
if (ischeck(s1.substr(0,i), s2.substr(0,i)) && ischeck(s1.substr(i, tsize-i),s2.substr(i, tsize-i)))
return 1;
if (ischeck(s1.substr(0,i), s2.substr(tsize-i, i)) && ischeck(s1.substr(i, tsize-i),s2.substr(0, tsize-i)))//交换
return 1;
}
return 0;
}
bool isScramble(string s1, string s2) //要有一个target
{
if (s1.size() != s2.size())
return 0;
return ischeck(s1, s2);
}
};