README.md

1496. Path Crossing

Given a string path, where path[i] = 'N', 'S', 'E' or 'W', each representing moving one unit north, south, east, or west, respectively. You start at the origin (0, 0) on a 2D plane and walk on the path specified by path.

Return True if the path crosses itself at any point, that is, if at any time you are on a location you've previously visited. Return False otherwise.

Example 1:

Input: path = "NES"
Output: false
Explanation: Notice that the path doesn't cross any point more than once.

Example 2:

Input: path = "NESWW"
Output: true
Explanation: Notice that the path visits the origin twice.

Constraints:

• 1 <= path.length <= 10^4
• path will only consist of characters in {'N', 'S', 'E', 'W}

Solutions (Rust)

1. Set

use std::collections::HashSet;

impl Solution {
    pub fn is_path_crossing(path: String) -> bool {
        let mut visited = HashSet::new();
        let mut x = 0;
        let mut y = 0;
        visited.insert((x, y));

        for dir in path.bytes() {
            match dir {
                b'N' => y += 1,
                b'S' => y -= 1,
                b'E' => x += 1,
                _ => x -= 1,
            };
            if !visited.insert((x, y)) {
                return true;
            }
        }

        false
    }
}