leetcode - 97.Interleaving String

Interleaving String

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2.

For example,

Given:

s1 =

"aabcc"

,

s2 =

"dbbca"

,

When s3 =

"aadbbcbcac"

, return

true

.

When s3 =

"aadbbbaccc"

, return

false

.

Solution:

public boolean isInterleave(String s1, String s2, String s3) {
if (s1.length() + s2.length() != s3.length())
return false;

boolean[][] matrix = new boolean[s2.length() + 1][s1.length() + 1];

matrix[0][0] = true;

for (int i = 1; i < matrix[0].length; i++) {
matrix[0][i] = matrix[0][i - 1] && (s1.charAt(i - 1) == s3.charAt(i - 1));
}

for (int i = 1; i < matrix.length; i++) {
matrix[i][0] = matrix[i - 1][0] && (s2.charAt(i - 1) == s3.charAt(i - 1));
}

for (int i = 1; i < matrix.length; i++) {
for (int j = 1; j < matrix[0].length; j++) {
matrix[i][j] = (matrix[i - 1][j] && (s2.charAt(i - 1) == s3.charAt(i + j - 1)))
|| (matrix[i][j - 1] && (s1.charAt(j - 1) == s3.charAt(i + j - 1)));
}
}

return matrix[s2.length()][s1.length()];
}