题目：

题解：

class Solution {public boolean isInterleave(String s1, String s2, String s3) {int n = s1.length(), m = s2.length(), t = s3.length();if (n + m != t) {return false;}boolean[] f = new boolean[m + 1];f[0] = true;for (int i = 0; i <= n; ++i) {for (int j = 0; j <= m; ++j) {int p = i + j - 1;if (i > 0) {f[j] = f[j] && s1.charAt(i - 1) == s3.charAt(p);}if (j > 0) {f[j] = f[j] || (f[j - 1] && s2.charAt(j - 1) == s3.charAt(p));}}}return f[m];}
}