feat(2018 day-12): generate checksums for a generation

Author: developher-net

2018/day-12/plants.js

@@ -122,6 +122,25 @@ class Plants {
     })
     return output.trim()
   }
+
+  /**
+   * Sums the number of plants present in all generations
+   */
+  getPlantTotal () {
+    return this.generations.reduce((gacc, g) => {
+      return gacc + g.filter((p) => p.state === '#').length
+    }, 0)
+  }
+
+  /**
+   * Generates a checksum calculated by summing the positions of all pots containing plants
+   * in a specified generation
+   * @param {Number} generation to generate checksum for
+   */
+  getCheckSum (generation) {
+    return this.generations[generation].filter((p) => p.state === '#')
+      .reduce((pacc, p) => pacc + p.position, 0)
+  }
 }
 
 module.exports = {

2018/day-12/plants.test.js

@@ -153,5 +153,27 @@ describe('--- Day 12: Subterranean Sustainability ---', () => {
         expect(actual).to.equal(expected)
       })
     })
+    describe('getPlantTotal', () => {
+      it('sums the total number of plants in all generations', () => {
+        const expected = 264
+        const plantTracker = new Plants(initialState, rules)
+        for (let gen = 1; gen <= 20; gen++) {
+          plantTracker.advance()
+        }
+        const actual = plantTracker.getPlantTotal()
+        expect(actual).to.equal(expected)
+      })
+    })
+    describe('getCheckSum(generation)', () => {
+      it('generates a checksum tallied by summing the positions of all pots containing plants', () => {
+        const expected = 325
+        const plantTracker = new Plants(initialState, rules)
+        for (let gen = 1; gen <= 20; gen++) {
+          plantTracker.advance()
+        }
+        const actual = plantTracker.getCheckSum(20)
+        expect(actual).to.equal(expected)
+      })
+    })
   })
 })