20240929 finished.

src/problem/mod.rs

@@ -249,3 +249,4 @@ mod p2306_naming_a_company;
 mod p2535_difference_between_element_sum_and_digit_sum_of_an_array;
 mod p2516_take_k_of_each_character_from_left_and_right;
 mod p2286_booking_concert_tickets_in_groups;
+mod p2073_time_needed_to_buy_tickets;

src/problem/p2073_time_needed_to_buy_tickets.rs

@@ -0,0 +1,54 @@
+/**
+ * [2073] Time Needed to Buy Tickets
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn time_required_to_buy(tickets: Vec<i32>, k: i32) -> i32 {
+        use std::collections::VecDeque;
+        let k = k as usize;
+        
+        let mut queue = VecDeque::with_capacity(tickets.len());
+        for (i, &v) in tickets.iter().enumerate() {
+            queue.push_back(if i == k {
+                (v, true)
+            } else {
+                (v, false)
+            });
+        }
+        
+        let mut second = 0;
+
+        loop {
+            let head = queue.pop_front().unwrap();
+            second += 1;
+            
+            if head.0 == 1 {
+                // 卖完了
+                if head.1 {
+                    break;
+                }
+            } else { 
+                queue.push_back((head.0 - 1, head.1));
+            }
+        }
+        
+        second
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2073() {
+        assert_eq!(6, Solution::time_required_to_buy(vec![2,3,2], 2));
+        assert_eq!(8, Solution::time_required_to_buy(vec![5,1,1,1], 0));
+    }
+}