Last Updated : 12 Jul, 2025
Try it on GfG Practice
Given two strings s1 and s2 of equal length, the task is to determine if s2 is a scrambled version of s1.
A scrambled string is formed by recursively splitting the string into two non-empty substrings and rearranging them randomly (s = x + y or s = y + x) and then recursively scramble the two substrings.
Note: A scrambled string is different from an anagram.
Examples:
[Naive Approach] Divide and Conquer Approach - Exponential TimeInput: s1="coder", s2="ocder"
Output: Yes
Explanation: "ocder" is a scrambled form of "coder"Input: s1="abcde", s2="caebd"
Output: No
Explanation: "caebd" is not a scrambled form of "abcde"
C++For s2[0..n-1] to be a scrambled version of s1[0..n-1], there must be an index i such that at least one of the following conditions holds true:
- s2[0...i] is a scrambled version of s1[0...i], and s2[i+1...n] is a scrambled version of s1[i+1...n].
- s2[0...i] is a scrambled version of s1[n-i...n], and s2[i+1...n] is a scrambled version of s1[0...n-i-1].
Note: A helpful optimization step is to check if the two strings are anagrams of each other beforehand. If they are not anagrams, it means the strings contain different characters and cannot be scrambled forms of each other.
// C++ Program to check if a
// given string is a scrambled
// form of another string
#include <bits/stdc++.h>
using namespace std;
bool isAnagram(string &s1, string &s2) {
vector<int> cnt(26, 0);
for (char ch: s1) cnt[ch-'a']++;
for (char ch: s2) cnt[ch-'a']--;
for (int i=0; i<26; i++) {
if (cnt[i]!=0) return false;
}
return true;
}
bool isScramble(string s1, string s2) {
// Strings of non-equal length
// cant' be scramble strings
if (s1.length() != s2.length()) {
return false;
}
int n = s1.length();
// Empty strings are scramble strings
if (n == 0) {
return true;
}
// Equal strings are scramble strings
if (s1 == s2) {
return true;
}
// Check for the condition of anagram
if (isAnagram(s1, s2) == false) {
return false;
}
for (int i = 1; i < n; i++) {
// Check if s2[0...i] is a scrambled
// string of s1[0...i] and if s2[i+1...n]
// is a scrambled string of s1[i+1...n]
if (isScramble(s1.substr(0, i), s2.substr(0, i))
&& isScramble(s1.substr(i, n - i),
s2.substr(i, n - i))) {
return true;
}
// Check if s2[0...i] is a scrambled
// string of s1[n-i...n] and s2[i+1...n]
// is a scramble string of s1[0...n-i-1]
if (isScramble(s1.substr(0, i),
s2.substr(n - i, i))
&& isScramble(s1.substr(i, n - i),
s2.substr(0, n - i))) {
return true;
}
}
// If none of the above
// conditions are satisfied
return false;
}
int main() {
string s1 = "coder";
string s2 = "ocred";
if (isScramble(s1, s2)) {
cout << "Yes";
}
else {
cout << "No";
}
return 0;
}
Java
// Java Program to check if a
// given string is a scrambled
// form of another string
import java.util.Arrays;
class GfG {
static boolean isAnagram(String s1, String s2) {
int[] cnt = new int[26];
for (char ch : s1.toCharArray()) cnt[ch - 'a']++;
for (char ch : s2.toCharArray()) cnt[ch - 'a']--;
for (int i = 0; i < 26; i++) {
if (cnt[i] != 0) return false;
}
return true;
}
static boolean isScramble(String s1, String s2) {
// Strings of non-equal length
// cant' be scramble strings
if (s1.length() != s2.length()) {
return false;
}
int n = s1.length();
// Empty strings are scramble strings
if (n == 0) {
return true;
}
// Equal strings are scramble strings
if (s1.equals(s2)) {
return true;
}
// Check for the condition of anagram
if (!isAnagram(s1, s2)) {
return false;
}
for (int i = 1; i < n; i++) {
// Check if s2[0...i] is a scrambled
// string of s1[0...i] and if s2[i+1...n]
// is a scrambled string of s1[i+1...n]
if (isScramble(s1.substring(0, i), s2.substring(0, i)) &&
isScramble(s1.substring(i), s2.substring(i))) {
return true;
}
// Check if s2[0...i] is a scrambled
// string of s1[n-i...n] and s2[i+1...n]
// is a scramble string of s1[0...n-i-1]
if (isScramble(s1.substring(0, i), s2.substring(n - i)) &&
isScramble(s1.substring(i), s2.substring(0, n - i))) {
return true;
}
}
// If none of the above
// conditions are satisfied
return false;
}
public static void main(String[] args) {
String s1 = "coder";
String s2 = "ocred";
if (isScramble(s1, s2)) {
System.out.println("Yes");
} else {
System.out.println("No");
}
}
}
Python
# Python Program to check if a
# given string is a scrambled
# form of another string
def isAnagram(s1, s2):
cnt = [0] * 26
for ch in s1:
cnt[ord(ch) - ord('a')] += 1
for ch in s2:
cnt[ord(ch) - ord('a')] -= 1
for i in range(26):
if cnt[i] != 0:
return False
return True
def isScramble(s1, s2):
# Strings of non-equal length
# cant' be scramble strings
if len(s1) != len(s2):
return False
n = len(s1)
# Empty strings are scramble strings
if n == 0:
return True
# Equal strings are scramble strings
if s1 == s2:
return True
# Check for the condition of anagram
if not isAnagram(s1, s2):
return False
for i in range(1, n):
# Check if s2[0...i] is a scrambled
# string of s1[0...i] and if s2[i+1...n]
# is a scrambled string of s1[i+1...n]
if isScramble(s1[:i], s2[:i]) and isScramble(s1[i:], s2[i:]):
return True
# Check if s2[0...i] is a scrambled
# string of s1[n-i...n] and s2[i+1...n]
# is a scramble string of s1[0...n-i-1]
if isScramble(s1[:i], s2[n - i:]) and isScramble(s1[i:], s2[:n - i]):
return True
# If none of the above
# conditions are satisfied
return False
if __name__ == "__main__":
s1 = "coder"
s2 = "ocred"
if isScramble(s1, s2):
print("Yes")
else:
print("No")
C#
// C# Program to check if a
// given string is a scrambled
// form of another string
using System;
class GfG {
static bool isAnagram(string s1, string s2) {
int[] cnt = new int[26];
foreach (char ch in s1) cnt[ch - 'a']++;
foreach (char ch in s2) cnt[ch - 'a']--;
for (int i = 0; i < 26; i++) {
if (cnt[i] != 0) return false;
}
return true;
}
static bool isScramble(string s1, string s2) {
// Strings of non-equal length
// cant' be scramble strings
if (s1.Length != s2.Length) {
return false;
}
int n = s1.Length;
// Empty strings are scramble strings
if (n == 0) {
return true;
}
// Equal strings are scramble strings
if (s1 == s2) {
return true;
}
// Check for the condition of anagram
if (!isAnagram(s1, s2)) {
return false;
}
for (int i = 1; i < n; i++) {
// Check if s2[0...i] is a scrambled
// string of s1[0...i] and if s2[i+1...n]
// is a scrambled string of s1[i+1...n]
if (isScramble(s1.Substring(0, i), s2.Substring(0, i)) &&
isScramble(s1.Substring(i), s2.Substring(i))) {
return true;
}
// Check if s2[0...i] is a scrambled
// string of s1[n-i...n] and s2[i+1...n]
// is a scramble string of s1[0...n-i-1]
if (isScramble(s1.Substring(0, i), s2.Substring(n - i)) &&
isScramble(s1.Substring(i), s2.Substring(0, n - i))) {
return true;
}
}
// If none of the above
// conditions are satisfied
return false;
}
static void Main() {
string s1 = "coder";
string s2 = "ocred";
if (isScramble(s1, s2)) {
Console.WriteLine("Yes");
} else {
Console.WriteLine("No");
}
}
}
JavaScript
// JavaScript Program to check if a
// given string is a scrambled
// form of another string
function isAnagram(s1, s2) {
let cnt = new Array(26).fill(0);
for (let ch of s1) cnt[ch.charCodeAt(0) - 'a'.charCodeAt(0)]++;
for (let ch of s2) cnt[ch.charCodeAt(0) - 'a'.charCodeAt(0)]--;
for (let i = 0; i < 26; i++) {
if (cnt[i] !== 0) return false;
}
return true;
}
function isScramble(s1, s2) {
if (s1.length !== s2.length) return false;
let n = s1.length;
if (n === 0) return true;
if (s1 === s2) return true;
if (!isAnagram(s1, s2)) return false;
for (let i = 1; i < n; i++) {
if (isScramble(s1.substring(0, i), s2.substring(0, i)) &&
isScramble(s1.substring(i), s2.substring(i))) return true;
if (isScramble(s1.substring(0, i), s2.substring(n - i)) &&
isScramble(s1.substring(i), s2.substring(0, n - i))) return true;
}
return false;
}
let s1 = "coder", s2 = "ocred";
console.log(isScramble(s1, s2) ? "Yes" : "No");
Time Complexity: O(2k+ 2(n-k)), where k and n-k are the length of the two substrings.
Auxiliary Space: O(2n), recursion stack.
The idea is to use dynamic programming to memoize subproblems where substrings of
s1ands2can be split and compared recursively under the scramble conditions. By capturing overlapping subproblems, we avoid redundant computations and improve efficiency.State Representation:
Definedp[i1][j1][i2][j2]astrueif the substrings1[i1...j1]can be scrambled intos2[i2...j2].Recurrence Relation:
For every possible split pointlen(1 ≤len<j1 - i1 + 1), check two scrambling conditions:
- No Swap:
Check if the firstlencharacters ofs1[i1...j1]ands2[i2...j2]are scrambles, and the remaining characters are scrambles:
- dp[i1][j1][i2][j2] |= dp[i1][i1+len-1][i2][i2+len-1] && dp[i1+len][j1][i2+len][j2]
- Swap:
Check if the firstlencharacters ofs1[i1...j1]match the lastlencharacters ofs2[i2...j2], and vice versa:
- dp[i1][j1][i2][j2] |= dp[i1][i1+len-1][j2-len+1][j2] && dp[i1+len][j1][i2][j2-len]
Base Case:
Ifi1 == j1(substring length 1), returns1[i1] == s2[i2].
C++Key Insight: The end indices
j1andj2can be derived from the start indicesi1,i2, and the substring lengthl(sincej1 = i1 + l - 1andj2 = i2 + l - 1). This eliminates redundant parameters. Now the states can be defined as:
- Define
dp[i1][i2][l]astrueif the substring starting ati1ins1with lengthlcan be scrambled into the substring starting ati2ins2with the same lengthl.Recurrence Relation:
For every possible splitlen(1 ≤len<l), check:
- No Swap: dp[i1][i2][l] |= dp[i1][i2][len] && dp[i1+len][i2+len][l-len]
- Swap: dp[i1][i2][l] |= dp[i1][i2 + (l-len)][len] && dp[i1+len][i2][l-len]
Base Case:
Ifl == 1, returns1[i1] == s2[i2].
// C++ Program to check if a
// given string is a scrambled
// form of another string
#include <bits/stdc++.h>
using namespace std;
bool scrambleRecur(int i1, int j1, int i2, int j2, string &s1, string &s2,
vector<vector<vector<vector<int>>>> &dp) {
// For single character, compare
// the two characters.
if (i1==j1) {
return s1[i1] == s2[i2];
}
// If value is computed, return it.
if (dp[i1][j1][i2][j2]!=-1) return dp[i1][j1][i2][j2];
bool ans = false;
int maxLen = j1-i1+1;
for (int len=1; len<maxLen; len++) {
// Check if s2[i2, i2+len-1] is scrambled version of s1[i1, i1+len-1]
// and s2[i2+len, j2] is scrambled version of s1[i1+len, j1].
bool val1 = scrambleRecur(i1, i1+len-1, i2, i2+len-1, s1, s2, dp) &&
scrambleRecur(i1+len, j1, i2+len, j2, s1, s2, dp);
// Check if s2[j2-len+1, j2] is scrambled version of s1[i1, i1+len-1]
// and s2[i2, j2-len] is scrambled version of s1[i1+len, j1].
bool val2 = scrambleRecur(i1, i1+len-1, j2-len+1, j2, s1, s2, dp) &&
scrambleRecur(i1+len, j1, i2, j2-len, s1, s2, dp);
// If any version is scrambled.
if (val1 || val2) {ans = true; break; }
}
// Memoize the value and return it.
return dp[i1][j1][i2][j2] = ans;
}
bool isScramble(string s1, string s2) {
int n = s1.length();
// Create a 4d array.
vector<vector<vector<vector<int>>>> dp(n,
vector<vector<vector<int>>>(n,
vector<vector<int>>(n, vector<int>(n, -1))));
return scrambleRecur(0, n-1, 0, n-1, s1, s2, dp);
}
int main() {
string s1 = "coder";
string s2 = "ocred";
if (isScramble(s1, s2)) {
cout << "Yes";
}
else {
cout << "No";
}
return 0;
}
Java
// Java Program to check if a
// given string is a scrambled
// form of another string
import java.util.Arrays;
class GfG {
static boolean scrambleRecur(int i1, int i2, int length,
String s1, String s2, int[][][] dp) {
// For single character, compare
// the two characters.
if (length == 1) {
return s1.charAt(i1) == s2.charAt(i2);
}
// If value is computed, return it.
if (dp[i1][i2][length] != -1) return dp[i1][i2][length] == 1;
boolean ans = false;
for (int len = 1; len < length; len++) {
// Check if s2[i2, i2+len-1] is scrambled version
// of s1[i1, i1+len-1] and s2[i2+len, i2+length-1] is
// scrambled version of s1[i1+len, i1+length-1].
boolean val1 = scrambleRecur(i1, i2, len, s1, s2, dp) &&
scrambleRecur(i1 + len, i2 + len, length - len, s1, s2, dp);
// Check if s2[i2+length-len+1, i2+length] is scrambled version
// of s1[i1, i1+len-1] and s2[i2, i2+length-len] is scrambled
// version of s1[i1+len, i1+length-1].
boolean val2 = scrambleRecur(i1, i2 + length - len, len, s1, s2, dp) &&
scrambleRecur(i1 + len, i2, length - len, s1, s2, dp);
// If any version is scrambled.
if (val1 || val2) {ans = true; break; }
}
// Memoize the value and return it.
dp[i1][i2][length] = ans ? 1 : 0;
return ans;
}
static boolean isScramble(String s1, String s2) {
int n = s1.length();
// Create a 3d array.
int[][][] dp = new int[n][n][n + 1];
for (int[][] arr2D : dp)
for (int[] arr1D : arr2D)
Arrays.fill(arr1D, -1);
return scrambleRecur(0, 0, n, s1, s2, dp);
}
public static void main(String[] args) {
String s1 = "coder";
String s2 = "ocred";
if (isScramble(s1, s2)) {
System.out.println("Yes");
} else {
System.out.println("No");
}
}
}
Python
# Python Program to check if a
# given string is a scrambled
# form of another string
def scrambleRecur(i1, i2, length, s1, s2, dp):
# For single character, compare
# the two characters.
if length == 1:
return s1[i1] == s2[i2]
# If value is computed, return it.
if dp[i1][i2][length] != -1:
return dp[i1][i2][length]
ans = False
for len_ in range(1, length):
# Check if s2[i2, i2+len-1] is scrambled version
# of s1[i1, i1+len-1] and s2[i2+len, i2+length-1]
# is scrambled version of s1[i1+len, i1+length-1].
val1 = scrambleRecur(i1, i2, len_, s1, s2, dp) and \
scrambleRecur(i1 + len_, i2 + len_, length - len_, s1, s2, dp)
# Check if s2[i2+length-len+1, i2+length] is scrambled
# version of s1[i1, i1+len-1] and s2[i2, i2+length-len]
# is scrambled version of s1[i1+len, i1+length-1].
val2 = scrambleRecur(i1, i2 + length - len_, len_, s1, s2, dp) and \
scrambleRecur(i1 + len_, i2, length - len_, s1, s2, dp)
# If any version is scrambled.
if (val1 or val2):
ans = True
break
# Memoize the value and return it.
dp[i1][i2][length] = ans
return ans
def isScramble(s1, s2):
n = len(s1)
# Create a 3d array.
dp = [[[-1] * (n + 1) for _ in range(n)] for _ in range(n)]
return scrambleRecur(0, 0, n, s1, s2, dp)
if __name__ == "__main__":
s1 = "coder"
s2 = "ocred"
if isScramble(s1, s2):
print("Yes")
else:
print("No")
C#
// C# Program to check if a
// given string is a scrambled
// form of another string
using System;
class GfG {
static bool scrambleRecur(int i1, int i2, int length,
string s1, string s2, int[,,] dp) {
// For single character, compare
// the two characters.
if (length == 1) {
return s1[i1] == s2[i2];
}
// If value is computed, return it.
if (dp[i1, i2, length] != -1)
return dp[i1, i2, length] == 1;
bool ans = false;
for (int len = 1; len < length; len++) {
// Check if s2[i2, i2+len-1] is scrambled version
// of s1[i1, i1+len-1] and s2[i2+len, i2+length-1]
// is scrambled version of s1[i1+len, i1+length-1].
bool val1 = scrambleRecur(i1, i2, len, s1, s2, dp) &&
scrambleRecur(i1 + len, i2 + len, length - len, s1, s2, dp);
// Check if s2[i2+length-len+1, i2+length] is scrambled
// version of s1[i1, i1+len-1] and s2[i2, i2+length-len]
// is scrambled version of s1[i1+len, i1+length-1].
bool val2 = scrambleRecur(i1, i2 + length - len, len, s1, s2, dp) &&
scrambleRecur(i1 + len, i2, length - len, s1, s2, dp);
// If any version is scrambled.
if (val1 || val2) {ans = true; break; }
}
// Memoize the value and return it.
dp[i1, i2, length] = ans ? 1 : 0;
return ans;
}
static bool isScramble(string s1, string s2) {
int n = s1.Length;
// Create a 3d array.
int[,,] dp = new int[n, n, n + 1];
for (int i = 0; i < n; i++)
for (int j = 0; j < n; j++)
for (int k = 0; k <= n; k++)
dp[i, j, k] = -1;
return scrambleRecur(0, 0, n, s1, s2, dp);
}
static void Main() {
string s1 = "coder";
string s2 = "ocred";
if (isScramble(s1, s2)) {
Console.WriteLine("Yes");
} else {
Console.WriteLine("No");
}
}
}
JavaScript
// JavaScript Program to check if a
// given string is a scrambled
// form of another string
function scrambleRecur(i1, i2, length, s1, s2, dp) {
// For single character, compare
// the two characters.
if (length === 1) {
return s1[i1] === s2[i2];
}
// If value is computed, return it.
if (dp[i1][i2][length] !== -1) return dp[i1][i2][length];
let ans = false;
for (let len = 1; len < length; len++) {
// Check if s2[i2, i2+len-1] is scrambled version
// of s1[i1, i1+len-1] and s2[i2+len, i2+length-1]
// is scrambled version of s1[i1+len, i1+length-1].
let val1 = scrambleRecur(i1, i2, len, s1, s2, dp) &&
scrambleRecur(i1 + len, i2 + len, length - len, s1, s2, dp);
// Check if s2[i2+length-len+1, i2+length] is scrambled
// version of s1[i1, i1+len-1] and s2[i2, i2+length-len]
// is scrambled version of s1[i1+len, i1+length-1].
let val2 = scrambleRecur(i1, i2 + length - len, len, s1, s2, dp) &&
scrambleRecur(i1 + len, i2, length - len, s1, s2, dp);
// If any version is scrambled.
if (val1 || val2) {ans = true; break; }
}
// Memoize the value and return it.
return dp[i1][i2][length] = ans;
}
function isScramble(s1, s2) {
let n = s1.length;
// Create a 3D array.
let dp = new Array(n).fill(0).map(() =>
new Array(n).fill(0).map(() =>
new Array(n + 1).fill(-1)
)
);
return scrambleRecur(0, 0, n, s1, s2, dp);
}
let s1 = "coder";
let s2 = "ocred";
if (isScramble(s1, s2)) {
console.log("Yes");
} else {
console.log("No");
}
Time Complexity: O(n^4), where n is the length of the given strings.
Auxiliary Space: O(n^3), due to memoization.
C++The idea is to fill the dp table from bottom to up. The table is filled in an iterative manner from len = 2 to n, i1 = 0 to n-1 and i2 = 0 to n-1.
Instead of maintaining 4 parameters (i1, j1, i2, j2), we maintain 3 parameters (i1, i2, len) as j1 - i1 is same as j2 - i2.
// C++ Program to check if a
// given string is a scrambled
// form of another string
#include <bits/stdc++.h>
using namespace std;
bool isScramble(string s1, string s2) {
int n = s1.length();
// dp[i1][i2][l] indicates whether
// s1.substr(i1, l) can scramble into s2.substr(i2, l)
vector<vector<vector<bool>>> dp(n,
vector<vector<bool>>(n, vector<bool>(n + 1, false)));
// Base case: substrings of length 1
for (int i1 = 0; i1 < n; ++i1) {
for (int i2 = 0; i2 < n; ++i2) {
dp[i1][i2][1] = (s1[i1] == s2[i2]);
}
}
// Fill DP table for lengths from 2 to n
for (int l = 2; l <= n; ++l) {
for (int i1 = 0; i1 <= n - l; ++i1) {
for (int i2 = 0; i2 <= n - l; ++i2) {
for (int len = 1; len < l; ++len) {
// Case 1: No swap
bool noSwap = dp[i1][i2][len] &&
dp[i1 + len][i2 + len][l - len];
// Case 2: Swap
bool swap = dp[i1][i2 + (l - len)][len] &&
dp[i1 + len][i2][l - len];
if (noSwap || swap) {
dp[i1][i2][l] = true;
break;
}
}
}
}
}
return dp[0][0][n];
}
int main() {
string s1 = "coder";
string s2 = "ocred";
if (isScramble(s1, s2)) {
cout << "Yes";
} else {
cout << "No";
}
return 0;
}
Java
// Java Program to check if a
// given string is a scrambled
// form of another string
class GfG {
static boolean isScramble(String s1, String s2) {
int n = s1.length();
// dp[i1][i2][l] indicates whether
// s1.substr(i1, l) can scramble into s2.substr(i2, l)
boolean[][][] dp = new boolean[n][n][n + 1];
// Base case: substrings of length 1
for (int i1 = 0; i1 < n; ++i1) {
for (int i2 = 0; i2 < n; ++i2) {
dp[i1][i2][1] = (s1.charAt(i1) == s2.charAt(i2));
}
}
// Fill DP table for lengths from 2 to n
for (int l = 2; l <= n; ++l) {
for (int i1 = 0; i1 <= n - l; ++i1) {
for (int i2 = 0; i2 <= n - l; ++i2) {
for (int len = 1; len < l; ++len) {
// Case 1: No swap
boolean noSwap = dp[i1][i2][len] &&
dp[i1 + len][i2 + len][l - len];
// Case 2: Swap
boolean swap = dp[i1][i2 + (l - len)][len] &&
dp[i1 + len][i2][l - len];
if (noSwap || swap) {
dp[i1][i2][l] = true;
break;
}
}
}
}
}
return dp[0][0][n];
}
public static void main(String[] args) {
String s1 = "coder";
String s2 = "ocred";
if (isScramble(s1, s2)) {
System.out.println("Yes");
} else {
System.out.println("No");
}
}
}
Python
# Python Program to check if a
# given string is a scrambled
# form of another string
def isScramble(s1, s2):
n = len(s1)
# dp[i1][i2][l] indicates whether
# s1[i1:i1+l] can scramble into s2[i2:i2+l]
dp = [[[False] * (n + 1) for _ in range(n)] for _ in range(n)]
# Base case: substrings of length 1
for i1 in range(n):
for i2 in range(n):
dp[i1][i2][1] = (s1[i1] == s2[i2])
# Fill DP table for lengths from 2 to n
for l in range(2, n + 1):
for i1 in range(n - l + 1):
for i2 in range(n - l + 1):
for length in range(1, l):
# Case 1: No swap
noSwap = dp[i1][i2][length] and dp[i1 + length][i2 + length][l - length]
# Case 2: Swap
swap = dp[i1][i2 + (l - length)][length] and dp[i1 + length][i2][l - length]
if noSwap or swap:
dp[i1][i2][l] = True
break
return dp[0][0][n]
if __name__ == "__main__":
s1 = "coder"
s2 = "ocred"
if isScramble(s1, s2):
print("Yes")
else:
print("No")
C#
// C# Program to check if a
// given string is a scrambled
// form of another string
using System;
class GfG {
static bool isScramble(string s1, string s2) {
int n = s1.Length;
// dp[i1][i2][l] indicates whether
// s1.Substring(i1, l) can scramble into s2.Substring(i2, l)
bool[,,] dp = new bool[n, n, n + 1];
// Base case: substrings of length 1
for (int i1 = 0; i1 < n; ++i1) {
for (int i2 = 0; i2 < n; ++i2) {
dp[i1, i2, 1] = (s1[i1] == s2[i2]);
}
}
// Fill DP table for lengths from 2 to n
for (int l = 2; l <= n; ++l) {
for (int i1 = 0; i1 <= n - l; ++i1) {
for (int i2 = 0; i2 <= n - l; ++i2) {
for (int len = 1; len < l; ++len) {
// Case 1: No swap
bool noSwap = dp[i1, i2, len] &&
dp[i1 + len, i2 + len, l - len];
// Case 2: Swap
bool swap = dp[i1, i2 + (l - len), len] &&
dp[i1 + len, i2, l - len];
if (noSwap || swap) {
dp[i1, i2, l] = true;
break;
}
}
}
}
}
return dp[0, 0, n];
}
static void Main() {
string s1 = "coder";
string s2 = "ocred";
if (isScramble(s1, s2)) {
Console.WriteLine("Yes");
} else {
Console.WriteLine("No");
}
}
}
JavaScript
// JavaScript Program to check if a
// given string is a scrambled
// form of another string
function isScramble(s1, s2) {
let n = s1.length;
// dp[i1][i2][l] indicates whether
// s1.substring(i1, i1 + l) can scramble into s2.substring(i2, i2 + l)
let dp = Array.from({ length: n }, () =>
Array.from({ length: n }, () =>
Array(n + 1).fill(false)
)
);
// Base case: substrings of length 1
for (let i1 = 0; i1 < n; ++i1) {
for (let i2 = 0; i2 < n; ++i2) {
dp[i1][i2][1] = (s1[i1] === s2[i2]);
}
}
// Fill DP table for lengths from 2 to n
for (let l = 2; l <= n; ++l) {
for (let i1 = 0; i1 <= n - l; ++i1) {
for (let i2 = 0; i2 <= n - l; ++i2) {
for (let len = 1; len < l; ++len) {
// Case 1: No swap
let noSwap = dp[i1][i2][len] &&
dp[i1 + len][i2 + len][l - len];
// Case 2: Swap
let swap = dp[i1][i2 + (l - len)][len] &&
dp[i1 + len][i2][l - len];
if (noSwap || swap) {
dp[i1][i2][l] = true;
break;
}
}
}
}
}
return dp[0][0][n];
}
let s1 = "coder";
let s2 = "ocred";
if (isScramble(s1, s2)) {
console.log("Yes");
} else {
console.log("No");
}
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