Unique Binary Search Trees

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Given n, how many structurally unique BST‘s (binary search trees) that store values 1...n?

For example,
Given n = 3, there are a total of 5 unique BST‘s.

   1         3     3      2      1
    \       /     /      / \           3     2     1      1   3      2
    /     /       \                    2     1         2                 3


卡特兰数
题解摘抄自： http://bangbingsyb.blogspot.com/2014/11/leetcode-unique-binary-search-trees-i-ii.html
“思路: Unique Binary Search Trees I

”

public class Solution {
    public int numTrees(int n) {
        int[] c= new int[n+1];
        c[0]=1;
        for(int nm = 1;nm<=n;nm++){
            for(int m=0;m<=nm-1;m++){
                c[nm] += c[m]*c[nm-m-1];
            }
        }
        return c[n];
    }
}

Unique Binary Search Trees

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原文地址：http://www.cnblogs.com/jiajiaxingxing/p/4562843.html