From deec485025fbec9ebee0bc9fe4e7a273e82691d2 Mon Sep 17 00:00:00 2001
From: FiveMovesAhead <ying@tig.foundation>
Date: Mon, 1 Dec 2025 15:21:26 +0000
Subject: [PATCH] Submitted knapsack/branch_and_bound

---
 .../src/knapsack/branch_and_bound/README.md   | 23 +++++
 .../src/knapsack/branch_and_bound/mod.rs      | 86 +++++++++++++++++++
 tig-algorithms/src/knapsack/mod.rs            |  3 +-
 3 files changed, 111 insertions(+), 1 deletion(-)
 create mode 100644 tig-algorithms/src/knapsack/branch_and_bound/README.md
 create mode 100644 tig-algorithms/src/knapsack/branch_and_bound/mod.rs

diff --git a/tig-algorithms/src/knapsack/branch_and_bound/README.md b/tig-algorithms/src/knapsack/branch_and_bound/README.md
new file mode 100644
index 00000000..42689bf5
--- /dev/null
+++ b/tig-algorithms/src/knapsack/branch_and_bound/README.md
@@ -0,0 +1,23 @@
+# TIG Code Submission
+
+## Submission Details
+
+* **Challenge Name:** knapsack
+* **Algorithm Name:** branch_and_bound
+* **Copyright:** 2024 Chad Blanchard
+* **Identity of Submitter:** Chad Blanchard
+* **Identity of Creator of Algorithmic Method:** null
+* **Unique Algorithm Identifier (UAI):** null
+
+## License
+
+The files in this folder are under the following licenses:
+* TIG Benchmarker Outbound License
+* TIG Commercial License
+* TIG Inbound Game License
+* TIG Innovator Outbound Game License
+* TIG Open Data License
+* TIG THV Game License
+
+Copies of the licenses can be obtained at:
+https://github.com/tig-foundation/tig-monorepo/tree/main/docs/licenses
\ No newline at end of file
diff --git a/tig-algorithms/src/knapsack/branch_and_bound/mod.rs b/tig-algorithms/src/knapsack/branch_and_bound/mod.rs
new file mode 100644
index 00000000..b84501a5
--- /dev/null
+++ b/tig-algorithms/src/knapsack/branch_and_bound/mod.rs
@@ -0,0 +1,86 @@
+// TIG's UI uses the pattern `tig_challenges::<challenge_name>` to automatically detect your algorithm's challenge
+
+use std::collections::VecDeque;
+use std::cmp::Ordering;
+use serde_json::{Map, Value};
+use tig_challenges::knapsack::*;
+
+#[derive(Clone, Debug)]
+struct Node {
+    level: usize,
+    profit: u32,
+    weight: u32,
+    bound: f64,
+}
+
+impl Node {
+    fn bound(&self, num_items: usize, max_weight: u32, weights: &[u32], values: &[u32]) -> f64 {
+        if self.weight >= max_weight {
+            return 0.0;
+        }
+        let mut profit_bound = self.profit as f64;
+        let mut j = self.level;
+        let mut total_weight = self.weight;
+        while j < num_items && total_weight + weights[j] <= max_weight {
+            total_weight += weights[j];
+            profit_bound += values[j] as f64;
+            j += 1;
+        }
+        if j < num_items {
+            profit_bound += (max_weight - total_weight) as f64 * values[j] as f64 / weights[j] as f64;
+        }
+        profit_bound
+    }
+}
+
+
+
+pub fn solve_challenge(
+    challenge: &Challenge,
+    save_solution: &dyn Fn(&Solution) -> anyhow::Result<()>,
+    hyperparameters: &Option<Map<String, Value>>,
+) -> anyhow::Result<()> {
+    let num_items = challenge.num_items as usize;
+    let max_weight = challenge.max_weight;
+    let values = &challenge.values;
+    let weights = &challenge.weights;
+
+    let mut queue: VecDeque<Node> = VecDeque::new();
+    let mut u = Node { level: 0, profit: 0, weight: 0, bound: 0.0 };
+    u.bound = u.bound(num_items, max_weight, weights, values);
+    queue.push_back(u.clone());
+
+    let mut max_profit = 0;
+    let mut best_items = vec![];
+
+    while let Some(node) = queue.pop_front() {
+        if node.bound > max_profit as f64 {
+            u.level = node.level + 1;
+            u.weight = node.weight + weights[u.level];
+            u.profit = node.profit + values[u.level];
+            u.bound = u.bound(num_items, max_weight, weights, values);
+
+            if u.weight <= max_weight && u.profit > max_profit {
+                max_profit = u.profit;
+                best_items.push(u.level);
+            }
+            if u.bound > max_profit as f64 {
+                queue.push_back(u.clone());
+            }
+
+            u.weight = node.weight;
+            u.profit = node.profit;
+            u.bound = u.bound(num_items, max_weight, weights, values);
+            if u.bound > max_profit as f64 {
+                queue.push_back(u.clone());
+            }
+        }
+    }
+
+    let _ = save_solution(&Solution { items: best_items });
+    return Ok(());
+}
+
+pub fn help() {
+    println!("No help information available.");
+}
diff --git a/tig-algorithms/src/knapsack/mod.rs b/tig-algorithms/src/knapsack/mod.rs
index 33ddf59d..002c4185 100644
--- a/tig-algorithms/src/knapsack/mod.rs
+++ b/tig-algorithms/src/knapsack/mod.rs
@@ -2,7 +2,8 @@
 
 // c003_a002
 
-// c003_a003
+pub mod branch_and_bound;
+pub use branch_and_bound as c003_a003;
 
 // c003_a004