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.
public class Solution {
public boolean isInterleave(String s1, String s2, String s3) {
int len1 = s1.length();
int len2 = s2.length();
int len3 = s3.length();
if (len1 + len2 != len3)
return false;
char[] chs1 = s1.toCharArray();
char[] chs2 = s2.toCharArray();
char[] chs3 = s3.toCharArray();
//dp[i][j]代表 chs1[1...i] chs2[1...j]能否顺序匹配chs3[i+j]
boolean[][] dp = new boolean[len1 + 1][len2 + 1];
dp[0][0] = true;
//s1中取0个s2中取i个 去和s3中0+i 个匹配
for (int i = 1; i <= len2; i++) {
dp[0][i] = dp[0][i - 1] && chs2[i - 1] == chs3[i - 1];
}
//s2中取0个s1中取i个 去和s3中0+i 个匹配
for (int i = 1; i <= len1; i++) {
dp[i][0] = dp[i - 1][0] && chs1[i - 1] == chs3[i - 1];
}
for(int i =1;i<=len1;i++)
for (int j=1;j<=len2;j++){
dp[i][j] = dp[i-1][j] && (chs3[i+j-1] == chs1[i-1])|| dp[i][j-1] && (chs3[i+j-1] == chs2[j-1]);
}
return dp[len1][len2];
}
}