Finish course 3 week 4 knapsack assignment

data/c3a4_knapsack1.txt

@@ -0,0 +1,101 @@
+10000 100
+16808 250
+50074 659
+8931 273
+27545 879
+77924 710
+64441 166
+84493 43
+7988 504
+82328 730
+78841 613
+44304 170
+17710 158
+29561 934
+93100 279
+51817 336
+99098 827
+13513 268
+23811 634
+80980 150
+36580 822
+11968 673
+1394 337
+25486 746
+25229 92
+40195 358
+35002 154
+16709 945
+15669 491
+88125 197
+9531 904
+27723 667
+28550 25
+97802 854
+40978 409
+8229 934
+60299 982
+28636 14
+23866 815
+39064 537
+39426 670
+24116 95
+75630 502
+46518 196
+30106 405
+19452 299
+82189 124
+99506 883
+6753 567
+36717 338
+54439 145
+51502 898
+83872 829
+11138 359
+53178 398
+22295 905
+21610 232
+59746 176
+53636 299
+98143 400
+27969 413
+261 558
+41595 9
+16396 969
+19114 531
+71007 963
+97943 366
+42083 853
+30768 822
+85696 713
+73672 902
+48591 832
+14739 58
+31617 791
+55641 680
+37336 7
+97973 99
+49096 320
+83455 224
+12290 761
+48906 127
+36124 507
+45814 771
+35239 95
+96221 845
+12367 535
+25227 395
+41364 739
+7845 591
+36551 160
+8624 948
+97386 218
+95273 540
+99248 386
+13497 886
+40624 421
+28145 969
+35736 916
+61626 535
+46043 12
+54680 153

src/knapsack.rs

@@ -0,0 +1,33 @@
+
+#[derive(Debug)]
+pub struct Knapsack {
+    pub size: usize,
+    pub n_items: usize,
+    pub items: Vec<Item>,
+}
+
+#[derive(Debug)]
+pub struct Item {
+	pub value: usize,
+	pub weight: usize,
+}
+
+pub fn knapsack(k: &Knapsack) -> usize {
+	let mut weight_to_value = vec![0; k.size];
+	for item_index in 0..k.n_items {
+		let mut new_weight_to_value = weight_to_value.to_vec();
+		let item = &k.items[item_index];
+		for weight in 0..k.size {
+			if weight >= item.weight {
+				let current_value = weight_to_value[weight];
+				let new_value = weight_to_value[weight - item.weight] + item.value;
+				if new_value > current_value {
+					new_weight_to_value[weight] = new_value;
+				}
+			}
+		}
+		weight_to_value = new_weight_to_value;
+	}
+
+	weight_to_value.pop().unwrap()
+}

src/main.rs

@@ -12,6 +12,7 @@ mod quick_sort;
 mod ssc;
 mod two_sum;
 mod util;
+mod knapsack;
 
 use crate::dijkstra::dijkstra;
 use crate::heap::heap;
@@ -25,6 +26,7 @@ use crate::quick_sort::quick_sort;
 use crate::ssc::ssc;
 use crate::two_sum::find_two_sums;
 use crate::mwis::mwis;
+use crate::knapsack::knapsack;
 use std::cmp::min;
 
 #[allow(dead_code)]
@@ -126,11 +128,23 @@ fn c3a3() {
     let s = util::read_max_weight_set("data/c3a3_mwis.txt").unwrap();
     let r3 = mwis(&s);
     println!("r1 = {} r2 = {} r3 = {:?}", r.1, r.0, r3);
+    // r1 = 19 r2 = 9 r3 = [1, 0, 1, 0, 0, 1, 1, 0]
 }
 
 #[allow(dead_code)]
 fn c3a4() {
-	println!("continue here");
+	let k1 = util::read_knapsack("data/c3a4_knapsack1.txt").unwrap();
+	let r1 = knapsack::knapsack(&k1);
+
+	let k2 = util::read_knapsack("data/c3a4_knapsack_big.txt").unwrap();
+	let r2 = knapsack::knapsack(&k2);
+	println!("r1 = {} r2 = {}", r1, r2);
+	// r1 = 2493893 r2 = 4243395
+}
+
+#[allow(dead_code)]
+fn c4a4() {
+	println!("Final course!");
 }
 
 fn main() {
@@ -143,6 +157,7 @@ fn main() {
     // c2a4();
     // c3a1();
     // c3a2();
-    c3a3();
+    // c3a3();
     c3a4();
+    c4a4();
 }

src/util.rs

@@ -6,6 +6,7 @@ use crate::min_cut;
 use crate::prims;
 use crate::ssc;
 use crate::mwis;
+use crate::knapsack;
 use std::fs::File;
 use std::io;
 use std::io::{BufRead, BufReader, Error, ErrorKind};
@@ -281,3 +282,31 @@ pub fn read_max_weight_set(path: &str) -> Result<mwis::IndependentSet, io::Error
     assert!(length == s.weights.len());
     Ok(s)
 }
+
+pub fn read_knapsack(path: &str) -> Result<knapsack::Knapsack, io::Error> {
+    let file = File::open(path)?;
+    let mut lines = BufReader::new(file).lines();
+    let line = lines.next().unwrap().unwrap();
+    let mut fields = line.split_whitespace();
+    let knapsack_size = fields.next().unwrap().parse().unwrap(); 
+    let number_of_items = fields.next().unwrap().parse().unwrap(); 
+    let mut k = knapsack::Knapsack {
+        size: knapsack_size,
+        n_items: number_of_items,
+        items: Vec::new(),
+    };
+
+    for line in lines {
+        let line = line?;
+        let mut fields = line.split_whitespace();
+        let value = fields.next().unwrap().parse().unwrap(); 
+        let weight = fields.next().unwrap().parse().unwrap(); 
+        let item = knapsack::Item {
+            value: value,
+            weight: weight,
+        };
+        k.items.push(item);
+    }
+
+    Ok(k)
+}