9565: ABC241 —— E - Putting Candies
[Creator : ]
Description
You are given a sequence $A=(A_0,A_1,\ldots,A_{N-1})$ of length $N$.
There is an initially empty dish. Takahashi is going to repeat the following operation $K$ times.
- Let $X$ be the number of candies on the dish. He puts $A_{(X\bmod N)}$ more candies on the dish. Here, $X\bmod N$ denotes the remainder when $X$ is divided by $N$.
Find how many candies are on the dish after the $K$ operations.
There is an initially empty dish. Takahashi is going to repeat the following operation $K$ times.
- Let $X$ be the number of candies on the dish. He puts $A_{(X\bmod N)}$ more candies on the dish. Here, $X\bmod N$ denotes the remainder when $X$ is divided by $N$.
Find how many candies are on the dish after the $K$ operations.
Input
Input is given from Standard Input in the following format:
```
$N$ $K$
$A_0$ $A_1$ $\ldots$ $A_{N-1}$
```
```
$N$ $K$
$A_0$ $A_1$ $\ldots$ $A_{N-1}$
```
Output
Print the answer.
Constraints
- $2 \leq N \leq 2\times 10^5$
- $1 \leq K \leq 10^{12}$
- $1 \leq A_i\leq 10^6$
- All values in input are integers.
- $1 \leq K \leq 10^{12}$
- $1 \leq A_i\leq 10^6$
- All values in input are integers.
Sample 1 Input
5 3
2 1 6 3 1
Sample 1 Output
11
The number of candies on the dish transitions as follows.
- In the 1-st operation, we have X=0, so $A_{(0\ \bmod\ {5})=A_0=2$ more candies will be put on the dish.
- In the 2-nd operation, we have X=2, so $A_{(2\ \bmod\ {5})=A_2=6$ more candies will be put on the dish.
- In the 3-rd operation, we have X=8, so $A_{(8\ \bmod\ {5})=A_3=3$ more candies will be put on the dish.
Thus, after the 3 operations, there will be 11 candies on the dish. Note that you must not print the remainder divided by N.
Sample 2 Input
10 1000000000000
260522 914575 436426 979445 648772 690081 933447 190629 703497 47202
Sample 2 Output
826617499998784056