【leetcode】Scramble String
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.
1. 如果两个substring相等的话,则为true
2. 如果两个substring中间某一个点,左边的substrings为scramble string, 同时右边的substrings也为scramble string,则为true
3. 如果两个substring中间某一个点,s1左边的substring和s2右边的substring为scramble string, 同时s1右边substring和s2左边的substring也为scramble string,则为true
2. 如果两个substring中间某一个点,左边的substrings为scramble string, 同时右边的substrings也为scramble string,则为true
3. 如果两个substring中间某一个点,s1左边的substring和s2右边的substring为scramble string, 同时s1右边substring和s2左边的substring也为scramble string,则为true
1 class Solution { 2 public: 3 bool isScramble(string s1, string s2) { 4 5 int n=s1.length(); 6 vector<vector<vector<bool>>> dp(n,vector<vector<bool>>(n,vector<bool>(n+1))); 7 //dp[i][j][k] represent whether s1[i,i+1,...,i+k-1] and s2[j,j+1,...,j+k-1] is scramble 8 9 10 for(int i=n-1;i>=0;i--) 11 { 12 for(int j=n-1;j>=0;j--) 13 { 14 for(int k=1;k<=n-max(i,j);k++) 15 { 16 if(s1.substr(i,k)==s2.substr(j,k)) 17 { 18 dp[i][j][k]=true; 19 } 20 else 21 { 22 for(int l=1;l<k;l++) 23 { 24 if(dp[i][j][l]&&dp[i+l][j+l][k-l]||dp[i][j+k-l][l]&&dp[i+l][j][k-l]) 25 { 26 dp[i][j][k]=true; 27 break; 28 } 29 } 30 31 } 32 } 33 } 34 35 } 36 return dp[0][0][n]; 37 } 38 };