merge intervals solution

Author: yhkee0404

merge-intervals/yhkee0404.rs

@@ -0,0 +1,21 @@
+use itertools::Itertools;
+use std::cmp::max;
+
+impl Solution {
+    pub fn merge(intervals: Vec<Vec<i32>>) -> Vec<Vec<i32>> {
+        let mut intervals: Vec<_> = intervals.iter()
+                .cloned()
+                .sorted_by(|a, b| a.cmp(b)) // T(n) = O(nlogn)
+                .collect();
+        let mut ans: Vec<Vec<i32>> = vec![];
+        let mut end = -1;
+        for interval in intervals {
+            if ans.is_empty() || ans.last().unwrap()[1] < interval[0] {
+                ans.push(interval) // S(n) = O(n)
+            } else {
+                ans.last_mut().unwrap()[1] = max(ans.last().unwrap()[1], interval[1])
+            }
+        }
+        ans
+    }
+}