Leetcode 96 Solution

This article provides solution to leetcode question 96 (unique-binary-search-trees)

https://leetcode.com/problems/unique-binary-search-trees

Solution

class Solution { public: int numTrees(int n) { vector<int> a; a.resize(n + 1);
a[0] = 1; a[1] = 1;
for (int i = 2; i <= n; i++) { a[i] = 0;
for (int j = 0; j <= i - 1; j++) { a[i] += a[j] * a[i - 1 - j]; } }
return a[n]; } };