Queries on a permutation with key

Array Binary Indexed Tree Simulation

84.9% acceptance

Feb 25, 2026

514

645

Given the array queries of positive integers between 1 and m, you have to process all queries[i] (from i=0 to i=queries.length-1) according to the following rules: In the beginning, you have the permutation P=[1,2,3,...,m]. For the current i, find the position of queries[i] in the permutation P (indexing from 0) and then move this at the beginning of the permutation P. Notice that the position of queries[i] in P is the result for queries[i]. Return an array containing the result for the given queries.

Solution

Rust

Time O(n)

Space O(n)

LeetCode

solution.rs

impl Solution {
  pub fn process_queries(queries: Vec<i32>, m: i32) -> Vec<i32> {
    let mut perm: Vec<i32> = (1..=m).collect();
    let mut result = vec![];
    for q in queries {
      let pos = perm.iter().position(|&x| x == q).unwrap();
      result.push(pos as i32);
      perm.remove(pos);
      perm.insert(0, q);
    }
    result
  }
}