from collections import deque
from typing import List
def jump_game(arr: List[int], start: int) -> bool:
seen = set()
queue = deque([start])
while queue:
size = len(queue)
for i in range(size):
cur = queue.popleft()
if arr[cur] == 0: return True
if cur in seen: continue
seen.add(cur)
if cur + arr[cur] < len(arr): queue.append(cur + arr[cur])
if cur - arr[cur] >= 0: queue.append(cur - arr[cur])
return False
if __name__ == '__main__':
arr = [int(x) for x in input().split()]
start = int(input())
res = jump_game(arr, start)
print('true' if res else 'false')
import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;
class Solution {
public static boolean jumpGame(List<Integer> arr, int start) {
if (arr.get(start) == 0) {
return true;
}
HashSet<Integer> visited = new HashSet<>();
visited.add(start);
ArrayDeque<Integer> queue = new ArrayDeque<>();
queue.offer(start);
while (queue.size() > 0) {
int curr = queue.poll();
if (arr.get(curr) == 0) {
return true;
}
int index = curr - arr.get(curr);
if (index >= 0 && !visited.contains(index)) {
visited.add(index);
queue.offer(index);
}
index = curr + arr.get(curr);
if (index < arr.size() && !visited.contains(index)) {
visited.add(index);
queue.offer(index);
}
}
return false;
}
public static List<String> splitWords(String s) {
return s.isEmpty() ? List.of() : Arrays.asList(s.split(" "));
}
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);
List<Integer> arr = splitWords(scanner.nextLine()).stream().map(Integer::parseInt).collect(Collectors.toList());
int start = Integer.parseInt(scanner.nextLine());
scanner.close();
boolean res = jumpGame(arr, start);
System.out.println(res);
}
}
function jumpGame(arr, start) {
if (arr[start] === 0) {
return true;
}
const visited = new Set();
visited.add(start);
const queue = [];
queue.push(start);
while (queue.length > 0) {
const curr = queue.shift();
if (arr[curr] === 0) {
return true;
}
let index = curr - arr[curr];
if (index >= 0 && !visited.has(index)) {
visited.add(index);
queue.push(index);
}
index = curr + arr[curr];
if (index < arr.length && !visited.has(index)) {
visited.add(index);
queue.push(index);
}
}
return false;
}
function splitWords(s) {
return s == "" ? [] : s.split(' ');
}
function* main() {
const arr = splitWords(yield).map((v) => parseInt(v));
const start = parseInt(yield);
const res = jumpGame(arr, start);
console.log(res);
}
class EOFError extends Error {}
{
const gen = main();
const next = (line) => gen.next(line).done && process.exit();
let buf = '';
next();
process.stdin.setEncoding('utf8');
process.stdin.on('data', (data) => {
const lines = (buf + data).split('\n');
buf = lines.pop();
lines.forEach(next);
});
process.stdin.on('end', () => {
buf && next(buf);
gen.throw(new EOFError());
});
}
