We have some permutation A of [0, 1, ..., N - 1], where N is the length of A.
The number of (global) inversions is the number of i < j with 0 <= i < j < N and A[i] > A[j].
The number of local inversions is the number of i with 0 <= i < N and A[i] > A[i+1].
Return true if and only if the number of global inversions is equal to the number of local inversions.
Example 1:
Input: A = [1,0,2] Output: true Explanation: There is 1 global inversion, and 1 local inversion.
Example 2:
Input: A = [1,2,0] Output: false Explanation: There are 2 global inversions, and 1 local inversion.
Note:
A will be a permutation of [0, 1, ..., A.length - 1].A will have length in range [1, 5000].struct Solution;
impl Solution {
fn is_ideal_permutation(a: Vec<i32>) -> bool {
let n = a.len();
for i in 0..n {
if (a[i] - i as i32).abs() > 1 {
return false;
}
}
true
}
}
#[test]
fn test() {
let a = vec![1, 0, 2];
let res = true;
assert_eq!(Solution::is_ideal_permutation(a), res);
let a = vec![1, 2, 0];
let res = false;
assert_eq!(Solution::is_ideal_permutation(a), res);
}