Added AOC 2021 day 03

www/statics/aoc/2021/03_solution.go

@@ -0,0 +1,102 @@
+package advent
+
+import (
+	"AdventOfCode2021/util"
+	"fmt"
+	"strconv"
+)
+
+func Day03Part1(ctx *util.AOCContext) (string, error) {
+
+	gamma := ""
+	epsilon := ""
+	for i := 0; i < 12; i++ {
+		mc, lc := getMostAndLeastCommonBit(ctx.InputLines(), i)
+		gamma += string(mc)
+		epsilon += string(lc)
+	}
+
+	intGamma, err := strconv.ParseInt(gamma, 2, 64)
+	if err != nil {
+		return "", err
+	}
+	intEpsilon, err := strconv.ParseInt(epsilon, 2, 64)
+	if err != nil {
+		return "", err
+	}
+
+	return fmt.Sprintf("%d", intGamma*intEpsilon), nil
+}
+
+func Day03Part2(ctx *util.AOCContext) (string, error) {
+	var err error
+
+	resOxy := int64(-1)
+	resCO2 := int64(-1)
+
+	valOxy := ctx.InputLines()
+	valCO2 := ctx.InputLines()
+	for i := 0; i < len(ctx.InputLines()[0]); i++ {
+		oxy, _ := getMostAndLeastCommonBit(valOxy, i)
+		_, co2 := getMostAndLeastCommonBit(valCO2, i)
+
+		ctx.Printf("MCB[Oxy]: %v\n\n", string(oxy))
+		ctx.Printf("LCB[CO2]: %v\n\n", string(co2))
+
+		newOxy := make([]string, 0)
+		newCO2 := make([]string, 0)
+
+		for _, v := range valOxy {
+			if v[i] == oxy {
+				newOxy = append(newOxy, v)
+			}
+		}
+		valOxy = newOxy
+
+		for _, v := range valCO2 {
+			if v[i] == co2 {
+				newCO2 = append(newCO2, v)
+			}
+		}
+		valCO2 = newCO2
+
+		if len(valOxy) == 1 {
+			resOxy, err = strconv.ParseInt(valOxy[0], 2, 64)
+			if err != nil {
+				return "", err
+			}
+			ctx.Printf("Oxy := %v\n\n", resOxy)
+		}
+
+		if len(valCO2) == 1 {
+			resCO2, err = strconv.ParseInt(valCO2[0], 2, 64)
+			if err != nil {
+				return "", err
+			}
+			ctx.Printf("CO2 := %v\n\n", resCO2)
+		}
+
+		ctx.Printf("CO2:\n%v\n\n", valCO2)
+		ctx.Printf("Oxy:\n%v\n\n", valOxy)
+	}
+
+	ctx.Printf("Result := %v * %v = %v\n\n", resOxy, resCO2, resOxy*resCO2)
+	return fmt.Sprintf("%d", resOxy*resCO2), nil
+}
+
+func getMostAndLeastCommonBit(lines []string, pos int) (uint8, uint8) {
+	count0 := 0
+	count1 := 0
+	for _, line := range lines {
+		if line[pos] == '0' {
+			count0++
+		} else {
+			count1++
+		}
+	}
+	if count1 >= count0 {
+		return '1', '0'
+	} else {
+		return '0', '1'
+	}
+}