题目描述
输入一个整数数组，判断该数组是不是某二叉搜索树的后序遍历的结果。如果是则输出Yes,否则输出No。假设输入的数组的任意两个数字都互不相同。
Java实现
public class Solution {
public boolean VerifySquenceOfBST(int[] sequence) {
if (sequence == null || sequence.length == 0)
return false;
return VerifySquenceOfBST(sequence, 0, sequence.length - 1);
}
private boolean VerifySquenceOfBST(int[] sequence, int first, int last) {
if (last - first <= 1)
return true;
int rootVal = sequence[last];
int cutIndex = first;
while (cutIndex < last && sequence[cutIndex++] < rootVal) ;
for (int i = cutIndex; i < last; i++) {
if (sequence[i] < rootVal)
return false;
}
return VerifySquenceOfBST(sequence, first, cutIndex - 1) && VerifySquenceOfBST(sequence, cutIndex, last - 1);
}
}
