Building Tower

5

1 votes
, Basic Math, C++, Math, Observation
Problem

Alex wants to build a tower of height \(N\) levels. He wants to build the tower as follows: the \(i^{th}\) level of the tower must have \(1 + 2 + ... + (i - 1) + i\) blocks, i.e., the top level of the tower must consist of \(1\) block, the second level must consist of \(1 + 2 = 3\) blocks, the third level must have \(1 + 2 + 3 = 6\) blocks, and so on. The numbering of levels is done from top to bottom.

Find the total number of blocks required to build a tower of height \(N\).

Input Format:

  • The first line contains an integer \(T\), which denotes the number of test cases.
  • The first line of each test case contains one integer \(N\), denoting the height of the tower.

Output Format:

For each test case, print the total number of blocks required to build a tower of height \(N\).

Constraints:

\(1 <= T <= 10^3\)

\(1 <= N <= 10^5\)

Time Limit: 2
Memory Limit: 256
Source Limit:
Explanation

For first test case:
\(N=4\), Alex uses \(1\) block on the \(1^{st}\) level, \(3\) blocks on the \(2^{nd}\) level, \(6\) blocks on the \(3^{rd}\) level, and \(10\) blocks on the \(4^{th}\) level of the tower. So, the total number of blocks required is \(1 + 3 + 6 + 10= 20\). Hence, \(20\) is the answer.

For second test case:
\(N=1\), Alex uses \(1\) block on the \(1^{st}\) level of the tower. So, the total number of blocks required is \(1\). Hence, \(1\) is the answer.

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