Partial sums

Given an array $A[0 ~..~ n-1]$ and an index $i$ , the $i$ -th partial sum of $A$ is $\sum_{0\le j\le i} A[j]$ . Here, you have to implement a data structure to efficiently compute partial sums. The operations you must consider are the creation of an array with all its values initialized to zero, the modification of a value, and the query of a partial sum.

Input

Input consists of a non-empty sequence of commands. Every command begins with a letter to identify it, followed by one or two integer-number parameters. These are the possible commands:

“r $n$ ” resets (or creates) an array of $n$ integer numbers to zero. Assume $1 \le n \le 10^5$ .
“s $i$ $x$ ” sets the possition $i$ to $x$ . Assume $0\le i< n$ and $-100\le x\le 100$ .
“g $i$ ” gets (and prints) the $i$ -th partial sum. Assume $0\le i< n$ .

In general, there are much more set and get commands than reset commands. The first command is always a reset.

Output

For each get command, print the corresponding partial sum. Print the output corresponding to each reset command on a unique line, separated by spaces.

Problem information

Author: Jordi Petit

Generation: 2026-01-25T11:35:07.529Z