add solution of napsack problem with dp

Author: n9te9

dynamic-programming/napsack.go

@@ -0,0 +1,77 @@
+// napsack Problem
+// https://www.geeksforgeeks.org/0-1-knapsack-problem-dp-10/
+package napsack
+
+// package main
+
+import (
+	"fmt"
+	"math"
+)
+
+type item struct {
+	weight int
+	value  int
+}
+
+func max(a, b int) int {
+	return int(math.Max(float64(a), float64(b)))
+}
+
+// display result of dp data structure
+func dist(dp [][]int) {
+	for i := 0; i < len(dp); i++ {
+		str := ""
+		for j := 0; j < len(dp[i]); j++ {
+			str = str + " " + fmt.Sprintf("%d", dp[i][j])
+		}
+		fmt.Println(str)
+	}
+}
+
+// solve napsack problem
+func solve(maxWeight int, items []item) [][]int {
+	n := len(items) + 1
+	m := maxWeight + 1
+	// create dp data structure
+	dp := make([][]int, n)
+	for i := range dp {
+		dp[i] = make([]int, m)
+	}
+	for i := 0; i < len(items); i++ {
+		for j := 0; j <= maxWeight; j++ {
+			if items[i].weight > j {
+				dp[i+1][j] = dp[i][j]
+			} else {
+				dp[i+1][j] = max(dp[i][j-items[i].weight]+items[i].value, dp[i][j])
+			}
+		}
+	}
+	return dp
+}
+
+// convert int slice into item slice
+func baseConv(base [][]int) []item {
+	var items []item
+	for i := 0; i < len(base); i++ {
+		var tmp item
+		tmp.weight = base[i][0]
+		tmp.value = base[i][1]
+		items = append(items, tmp)
+	}
+	return items
+}
+
+/*
+func main() {
+	maxWeight := 50
+	base := [][]int{
+		{10, 60},
+		{20, 100},
+		{30, 120},
+	}
+	items := baseConv(base)
+	dp := solve(maxWeight, items)
+	dist(dp)
+}
+*/