diff --git a/src/problem/mod.rs b/src/problem/mod.rs
index 2998bfb..fcfa8d4 100644
--- a/src/problem/mod.rs
+++ b/src/problem/mod.rs
@@ -28,4 +28,5 @@ mod p670_maximum_swap;
 mod p2765_longest_alternating_subarray;
 mod p2865_beautiful_towers_i;
 mod p2859_sum_of_values_at_indices_with_k_set_bits;
-mod p2846_minimum_edge_weight_equilibrium_queries_in_a_tree;
\ No newline at end of file
+mod p2846_minimum_edge_weight_equilibrium_queries_in_a_tree;
+mod p2861_maximum_number_of_alloys;
\ No newline at end of file
diff --git a/src/problem/p2861_maximum_number_of_alloys.rs b/src/problem/p2861_maximum_number_of_alloys.rs
new file mode 100644
index 0000000..066b351
--- /dev/null
+++ b/src/problem/p2861_maximum_number_of_alloys.rs
@@ -0,0 +1,75 @@
+/**
+ * [2861] Maximum Number of Alloys
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    fn check(n: usize, count: i32, budget: i32, composition: &Vec<i32>, stock: &Vec<i32>, cost: &Vec<i32>) -> bool {
+        let mut need = 0i64;
+
+        for i in 0..n {
+            let number = composition[i] * count - stock[i];
+
+            if number > 0 {
+                need += number as i64 * cost[i] as i64;
+            }
+        }
+
+        need <= budget as i64
+    }
+
+    pub fn max_number_of_alloys(n: i32, k: i32, budget: i32,
+                                composition: Vec<Vec<i32>>, stock: Vec<i32>, cost: Vec<i32>) -> i32 {
+        let mut result = 0;
+        let (n, k) = (n as usize, k as usize);
+
+        for m in 0..k {
+            let mut left = 0;
+            let mut right = vec![0;n];
+
+            for i in 0..n {
+                right[i] = (stock[i] + budget / cost[i]) / composition[m][i];
+            }
+
+            let mut right = *right.iter().max().unwrap();
+
+            while left < right {
+                let mid = (left + right) / 2;
+
+                if Solution::check(n, mid, budget, &composition[m], &stock, &cost) {
+                    left = mid + 1;
+                } else {
+                    right = mid;
+                }
+
+                dbg!(left, right);
+            }
+
+            if !Solution::check(n, left, budget, &composition[m], &stock, &cost) {
+                left = left - 1;
+            }
+
+            result = result.max(left);
+        }
+        result
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_2861() {
+        assert_eq!(Solution::max_number_of_alloys(3,2,15,
+                                                  vec![vec![1,1,1], vec![1,1,10]],
+                                                  vec![0,0,0],
+                                                  vec![1,2,3]),
+                   2);
+    }
+}