20241007 finished.

src/problem/mod.rs

@@ -256,3 +256,4 @@ mod p1870_minimum_speed_to_arrive_on_time;
 mod p1928_minimum_cost_to_reach_destination_in_time;
 mod p1227_airplane_seat_assignment_probability;
 mod p2187_minimum_time_to_complete_trips;
+mod p871_minimum_number_of_refueling_stops;

src/problem/p871_minimum_number_of_refueling_stops.rs

@@ -0,0 +1,55 @@
+/**
+ * [871] Minimum Number of Refueling Stops
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn min_refuel_stops(target: i32, start_fuel: i32, stations: Vec<Vec<i32>>) -> i32 {
+        use std::collections::BinaryHeap;
+        let mut stations: Vec<(i32, i32)> = stations.iter().map(|v| (v[0], v[1])).collect();
+        stations.push((target, 0));
+
+        let mut heap = BinaryHeap::new();
+        let mut fuel = start_fuel;
+        let mut last_pos = 0;
+        let mut count = 0;
+
+        for (p, f) in stations {
+            while fuel < p - last_pos {
+                if let Some(head) = heap.pop() {
+                    fuel += head;
+                    count += 1;
+                } else {
+                    return -1;
+                }
+            }
+
+            fuel -= p - last_pos;
+            last_pos = p;
+            heap.push(f);
+        }
+
+        if fuel >= 0 {
+            count
+        } else {
+            -1
+        }
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_871() {
+        assert_eq!(0, Solution::min_refuel_stops(1, 1, vec![]));
+        assert_eq!(-1, Solution::min_refuel_stops(100, 1, vec![vec![10, 100]]));
+        assert_eq!(2, Solution::min_refuel_stops(100, 10, vec![vec![10, 60], vec![20, 30], vec![30, 30], vec![60, 40]]));
+    }
+}