leetcode/src/problem/p210_course_schedule_ii.rs
2024-10-24 09:08:13 +08:00

62 lines
1.3 KiB
Rust

/**
* [210] Course Schedule II
*/
pub struct Solution {}
// submission codes start here
use std::collections::VecDeque;
impl Solution {
pub fn find_order(num_courses: i32, prerequisites: Vec<Vec<i32>>) -> Vec<i32> {
let num = num_courses as usize;
let mut edges = vec![vec![]; num];
let mut in_degs = vec![0; num];
for edge in prerequisites {
let (x, y) = (edge[1] as usize, edge[0] as usize);
edges[x].push(y);
in_degs[y] += 1;
}
let mut queue = VecDeque::new();
for i in 0..num {
if in_degs[i] == 0 {
queue.push_back(i);
}
}
let mut result = vec![];
while !queue.is_empty() {
let node = queue.pop_front().unwrap();
result.push(node);
for &next in &edges[node] {
in_degs[next] -= 1;
if in_degs[next] == 0 {
queue.push_back(next);
}
}
}
if result.len() != num {
vec![]
} else {
result.iter().map(|x| *x as i32).collect()
}
}
}
// submission codes end
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_210() {}
}