Given a list of intervals, remove all intervals that are covered by another interval in the list.
Interval [a,b) is covered by interval [c,d) if and only if c <= a and b <= d.
After doing so, return the number of remaining intervals.
Example 1:
Input: intervals = [[1,4],[3,6],[2,8]] Output: 2 Explanation: Interval [3,6] is covered by [2,8], therefore it is removed.
Example 2:
Input: intervals = [[1,4],[2,3]] Output: 1
Example 3:
Input: intervals = [[0,10],[5,12]] Output: 2
Example 4:
Input: intervals = [[3,10],[4,10],[5,11]] Output: 2
Example 5:
Input: intervals = [[1,2],[1,4],[3,4]] Output: 1
Constraints:
1 <= intervals.length <= 1000intervals[i].length == 20 <= intervals[i][0] < intervals[i][1] <= 10^5struct Solution;
use std::cmp::Reverse;
impl Solution {
fn remove_covered_intervals(mut intervals: Vec<Vec<i32>>) -> i32 {
intervals.sort_by_key(|v| (v[0], Reverse(v[1])));
let n = intervals.len();
let mut r = -1;
let mut res = 0;
for i in 0..n {
let interval = &intervals[i];
if interval[1] <= r {
continue;
} else {
r = interval[1];
res += 1;
}
}
res
}
}
#[test]
fn test() {
let intervals = vec_vec_i32![[1, 4], [3, 6], [2, 8]];
let res = 2;
assert_eq!(Solution::remove_covered_intervals(intervals), res);
}