1152. Analyze User Website Visit Pattern
We are given some website visits: the user with name username[i]
visited the website website[i]
at time timestamp[i]
.
A 3-sequence is a list of websites of length 3 sorted in ascending order by the time of their visits. (The websites in a 3-sequence are not necessarily distinct.)
Find the 3-sequence visited by the largest number of users. If there is more than one solution, return the lexicographically smallest such 3-sequence.
Example 1:
Input: username = ["joe","joe","joe","james","james","james","james","mary","mary","mary"], timestamp = [1,2,3,4,5,6,7,8,9,10], website = ["home","about","career","home","cart","maps","home","home","about","career"] Output: ["home","about","career"] Explanation: The tuples in this example are: ["joe", 1, "home"] ["joe", 2, "about"] ["joe", 3, "career"] ["james", 4, "home"] ["james", 5, "cart"] ["james", 6, "maps"] ["james", 7, "home"] ["mary", 8, "home"] ["mary", 9, "about"] ["mary", 10, "career"] The 3-sequence ("home", "about", "career") was visited at least once by 2 users. The 3-sequence ("home", "cart", "maps") was visited at least once by 1 user. The 3-sequence ("home", "cart", "home") was visited at least once by 1 user. The 3-sequence ("home", "maps", "home") was visited at least once by 1 user. The 3-sequence ("cart", "maps", "home") was visited at least once by 1 user.
Note:
3 <= N = username.length = timestamp.length = website.length <= 50
1 <= username[i].length <= 10
0 <= timestamp[i] <= 10^9
1 <= website[i].length <= 10
- Both
username[i]
andwebsite[i]
contain only lowercase characters. - It is guaranteed that there is at least one user who visited at least 3 websites.
- No user visits two websites at the same time.
Rust Solution
struct Solution;
use std::collections::HashMap;
use std::collections::HashSet;
type Sequence = (String, String, String);
impl Solution {
fn most_visited_pattern(
mut username: Vec<String>,
mut timestamp: Vec<i32>,
mut website: Vec<String>,
) -> Vec<String> {
let mut hm: HashMap<String, Vec<(i32, String)>> = HashMap::new();
let mut sequences: HashMap<Sequence, HashSet<String>> = HashMap::new();
while let (Some(u), Some(t), Some(w)) = (username.pop(), timestamp.pop(), website.pop()) {
hm.entry(u).or_default().push((t, w));
}
for (u, p) in hm.iter_mut() {
p.sort_unstable_by_key(|p| p.0);
let n = p.len();
for i in 0..n {
for j in i + 1..n {
for k in j + 1..n {
let sequence = (p[i].1.to_string(), p[j].1.to_string(), p[k].1.to_string());
sequences.entry(sequence).or_default().insert(u.to_string());
}
}
}
}
let mut max = 0;
let mut res = ("".to_string(), "".to_string(), "".to_string());
for (sequence, hs) in sequences {
if hs.len() > max {
max = hs.len();
res = sequence;
} else if hs.len() == max && sequence < res {
res = sequence;
}
}
vec![res.0, res.1, res.2]
}
}
#[test]
fn test() {
let username = vec_string![
"joe", "joe", "joe", "james", "james", "james", "james", "mary", "mary", "mary"
];
let timestamp = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
let website = vec_string![
"home", "about", "career", "home", "cart", "maps", "home", "home", "about", "career"
];
let res = vec_string!["home", "about", "career"];
assert_eq!(
Solution::most_visited_pattern(username, timestamp, website),
res
);
}
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