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use std::collections::VecDeque;
struct Solution;
impl Solution {
pub fn can_reach(arr: Vec<i32>, start: i32) -> bool {
let mut arr = arr;
let mut vd: VecDeque<i32> = VecDeque::with_capacity(arr.len());
vd.push_back(start);
while let Some(front) = vd.pop_front() {
match arr[front as usize].cmp(&0) {
std::cmp::Ordering::Less => continue,
std::cmp::Ordering::Equal => return true,
std::cmp::Ordering::Greater => {
if front - arr[front as usize] >= 0 {
vd.push_back(front - arr[front as usize]);
}
if front + arr[front as usize] < arr.len() as i32 {
vd.push_back(front + arr[front as usize]);
}
arr[front as usize] = -1;
}
}
}
false
}
}
fn main() {
let arr1 = vec![4,2,3,0,3,1,2];
let arr2 = vec![4,2,3,0,3,1,2];
let arr3 = vec![3,0,2,1,2];
println!("{}", Solution::can_reach(arr1, 5)); //true
println!("{}", Solution::can_reach(arr2, 0)); //true
println!("{}", Solution::can_reach(arr3, 2)); //false
}
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