975

Author: caibirdme

src/lib.rs

@@ -316,6 +316,7 @@ mod prob_932;
 mod prob_946;
 mod prob_973;
 mod prob_974;
+mod prob_975;
 mod prob_995;
 mod prob_1000;
 mod prob_1002;

src/prob_975.rs

@@ -0,0 +1,52 @@
+use std::collections::BTreeMap;
+use std::ops::Bound::{Included, Unbounded};
+
+impl Solution {
+    pub fn odd_even_jumps(a: Vec<i32>) -> i32 {
+        let n = a.len();
+        if n == 1 {
+            return 1;
+        }
+        let mut ans = 1;
+        let mut bt = BTreeMap::new();
+        let mut odd = vec![false; n];
+        let mut even = vec![false; n];
+        bt.insert(a[n-1], n-1);
+        for i in (0..n-1).rev() {
+            let cur = a[i];
+            if let Some((_, &pos)) = bt.range((Included(&cur), Unbounded)).next() {
+                if pos == n-1 || even[pos] {
+                    odd[i] = true;
+                    ans += 1
+                }
+            }
+            if let Some((_, &pos)) = bt.range((Unbounded, Included(&cur))).rev().next() {
+                if pos == n-1 || odd[pos] {
+                    even[i] = true;
+                }
+            }
+            bt.insert(cur, i);
+        }
+        ans
+    }
+}
+
+struct Solution;
+
+#[cfg(test)]
+mod tests {
+    use super::Solution;
+
+    #[test]
+    fn test_odd_even_jumps() {
+        let test_cases = vec![
+            (vec![81,54,96,60,58], 2),
+            (vec![10,13,12,14,15], 2),
+            (vec![2,3,1,1,4], 3),
+            (vec![5,1,3,4,2], 3),
+        ];
+        for (arr, expect) in test_cases {
+            assert_eq!(Solution::odd_even_jumps(arr.clone()), expect, "arr: {:?}", arr);
+        }
+    }
+}