Ejemplo 1: mochila python 0-1
#Returns the maximum value that can be stored by the bag
def knapSack(W, wt, val, n):
# initial conditions
if n == 0 or W == 0 :
return 0
# If weight is higher than capacity then it is not included
if (wt[n-1] > W):
return knapSack(W, wt, val, n-1)
# return either nth item being included or not
else:
return max(val[n-1] + knapSack(W-wt[n-1], wt, val, n-1),
knapSack(W, wt, val, n-1))
# To test above function
val = [50,100,150,200]
wt = [8,16,32,40]
W = 64
n = len(val)
print (knapSack(W, wt, val, n))
Ejemplo 2: algoritmo de mochila en python
# a dynamic approach
# Returns the maximum value that can be stored by the bag
def knapSack(W, wt, val, n):
K = [[0 for x in range(W + 1)] for x in range(n + 1)]
#Table in bottom up manner
for i in range(n + 1):
for w in range(W + 1):
if i == 0 or w == 0:
K[i][w] = 0
elif wt[i-1] <= w:
K[i][w] = max(val[i-1] + K[i-1][w-wt[i-1]], K[i-1][w])
else:
K[i][w] = K[i-1][w]
return K[n][W]
#Main
val = [50,100,150,200]
wt = [8,16,32,40]
W = 64
n = len(val)
print(knapSack(W, wt, val, n))
Ejemplo 3: problema de la mochila
// memory efficient and iterative approach to the knapsack problem
#include <bits/stdc++.h>
using namespace std;
// n is the number of items
// w is the knapsack's capacity
int n, w;
int main() {
/*
input format:
n w
value_1 cost_1
value_2 cost_2
.
.
value_n cost_n
*/
cin >> n >> w;
vector<long long> dp(w + 1, 0);
for (int i = 0; i < n; ++i) {
int value, cost;
cin >> value >> cost;
for (int j = w; j >= cost; --j)
dp[j] = max(dp[j], value + dp[j - cost]);
}
// the answer is dp[w]
cout << dp[w];
}
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