Optimization complete!

I no longer create new objects for ops, modes, or values. Instead I
always update the same objects (modes / values are arrays) in place,
which helps a lot! Looks like around a 3x speed improvement.

Modes is a single array which is possible since we know the number of
params. We loop through params which means we don't hit the end of the
modes if the op doesn't need it.

Values needed to be separate arrays on each op since we spread this out
into the function call. Not a big deal since we create these arrays in
the constructor.

Author: romellem

2019/19/intcode-computer.js

@@ -141,8 +141,13 @@ class Computer {
 			},
 		};
 
-		this.maxParams = Math.max(...Object.values(this.OPS).map(v => v.params));
-		this.sharedModes = Array(this.maxParams).fill('0');
+		const ops_list = Object.values(this.OPS);
+		const max_params = Math.max(...ops_list.map(v => v.params));
+		const shared_modes = Array(max_params).fill('0');
+		for (let op of ops_list) {
+			op.modes = shared_modes;
+			op.values = Array(op.params).fill(0);
+		}
 
 		this.halted = false;
 	}
@@ -176,8 +181,6 @@ class Computer {
 
 		let full_op = temp_op.padStart(op.params + 2, '0');
 
-		let modes = this.sharedModes;
-
 		// "Parameter modes are single digits, one per parameter, read **right-to-left** from the opcode"
 		for (let i = op.params - 1; i >= 0; i--) {
 			// [0,1,2,3,4,5]
@@ -188,18 +191,16 @@ class Computer {
 			// 2 -> 3 # |(2 - 6 + 1)| = |-3| = 3
 			// 1 -> 4 # |(1 - 6 + 1)| = |-4| = 4
 			// 0 -> 5 # |(0 - 6 + 1)| = |-5| = 5
-			modes[Math.abs(i - op.params + 1)] = full_op[i];
+			op.modes[Math.abs(i - op.params + 1)] = full_op[i];
 		}
 
-		op.modes = modes;
 		let end = new Date();
 		this.parseOpTime += (end - start);
 		return op;
 	}
 
-	runOp({ modes, params, fn, jumps, write }) {
+	runOp({ modes, values, params, fn, jumps, write }) {
 		this.pointer++;
-		let values = [];
 		for (let i = 0; i < params; i++) {
 			let mode = modes[i];
 			let value = this.memory[this.pointer + i];
@@ -294,7 +295,7 @@ class Computer {
 				value = 0;
 			}
 
-			values.push(value);
+			values[i] = value;
 		}
 
 		// If result is `true`, we moved the pointer

2019/19/part-two.js

@@ -2,6 +2,6 @@ const { input } = require('./input');
 const { TractorBeam } = require('./tractor-beam');
 
 let tractor_beam = new TractorBeam(input);
-// console.log(tractor_beam.partTwo());
-console.log(tractor_beam.partTwoOptimized());
+console.log(tractor_beam.partTwo());
+// console.log(tractor_beam.partTwoOptimized());
 console.log(`parseOp took ${tractor_beam.parseOpTime} ms`);