From 12d3a89857741ceeb803221de91865d07c93b871 Mon Sep 17 00:00:00 2001
From: jackfiled <xcrenchangjun@outlook.com>
Date: Wed, 4 Sep 2024 10:41:21 +0800
Subject: [PATCH] 20240904 finished.

---
 src/problem/mod.rs                  |  3 +-
 src/problem/p2860_happy_students.rs | 46 +++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 1 deletion(-)
 create mode 100644 src/problem/p2860_happy_students.rs

diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index 3945276..eadaa66 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -224,4 +224,5 @@ mod p3153_sum_of_digit_differences_of_all_pairs;
 mod p3127_make_a_square_with_the_same_color;
 mod p1450_number_of_students_doing_homework_at_a_given_time;
 mod p2024_maximize_the_confusion_of_an_exam;
-mod p2708_maximum_strength_of_a_group;
\ No newline at end of file
+mod p2708_maximum_strength_of_a_group;
+mod p2860_happy_students;
\ No newline at end of file
diff --git a/src/problem/p2860_happy_students.rs b/src/problem/p2860_happy_students.rs
new file mode 100644
index 0000000..627a474
--- /dev/null
+++ b/src/problem/p2860_happy_students.rs
@@ -0,0 +1,46 @@
+/**
+ * [2860] Happy Students
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn count_ways(nums: Vec<i32>) -> i32 {
+        let mut nums: Vec<usize> = nums.iter().map(|x| *x as usize).collect();
+        let n = nums.len();
+        nums.sort();
+
+        // 是否能不选中任何学生
+        let mut result = 0; 
+
+        for i in 0..=n {
+            if i > 0 && nums[i - 1] >= i {
+                continue;
+            } 
+            
+            if i < n && nums[i] <= i {
+                continue;
+            }
+            
+            result += 1;
+        }
+
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2860() {
+        assert_eq!(2, Solution::count_ways(vec![1, 1]));
+        assert_eq!(3, Solution::count_ways(vec![6, 0, 3, 3, 6, 7, 2, 7]));
+        assert_eq!(1, Solution::count_ways(vec![1, 0, 1, 1]));
+    }
+}