этот код может найти максимальное значение ранца в наборе данных. Мне нужно опубликовать путь, хотя в файле .txt в формате, как 0,1,0,1,1,0 ......, что означает 1-й элемент = 0 (не включены) 2-й элемент = 1 (включены в решение) ... есть предложения? проверенная таблица [n] существует для того, чтобы сохранить путь, а затем сохранить в файле
#include <bits/stdc++.h>
using namespace std;
// Structure for Item which store weight and corresponding
// value of Item
struct Item
{
float weight;
int value;
};
// Node structure to store information of decision
// tree
struct Node
{
// level --> Level of node in decision tree (or index
// in arr[]
// profit --> Profit of nodes on path from root to this
// node (including this node)
// bound ---> Upper bound of maximum profit in subtree
// of this node/
int level, profit, bound;
float weight;
};
// Comparison function to sort Item according to
// val/weight ratio
bool cmp(Item a, Item b)
{
double r1 = (double)a.value / a.weight;
double r2 = (double)b.value / b.weight;
return r1 > r2;
}
// Returns bound of profit in subtree rooted with u.
// This function mainly uses Greedy solution to find
// an upper bound on maximum profit.
int bound(Node u, int n, int W, Item arr[])
{
// if weight overcomes the knapsack capacity, return
// 0 as expected bound
if (u.weight >= W)
return 0;
// initialize bound on profit by current profit
int profit_bound = u.profit;
// start including items from index 1 more to current
// item index
int j = u.level + 1;
int totweight = u.weight;
// checking index condition and knapsack capacity
// condition
while ((j < n) && (totweight + arr[j].weight <= W))
{
totweight += arr[j].weight;
profit_bound += arr[j].value;
j++;
}
// If k is not n, include last item partially for
// upper bound on profit
if (j < n)
profit_bound += (W - totweight) * arr[j].value /
arr[j].weight;
return profit_bound;
}
// Returns maximum profit we can get with capacity W
int knapsack(int W, int ** tab, int n)
{
FILE *bbdfs=fopen("pr1.txt","a");
int checked[n];//array to store chosen values in 0 & 1
int i;
for(i=0;i<n;i++){
checked[i]=0;
}
Item arr[n];
for(i=0;i<n;i++){
arr[i].value=tab[i][1];
arr[i].weight=tab[i][0];
}
// sorting Item on basis of value per unit
// weight.
/// sort(arr, arr + n, cmp);
// make a queue for traversing the node
queue<Node> Q;
Node u, v;
// dummy node at starting
u.level = -1;
u.profit = u.weight = 0;
Q.push(u);
// One by one extract an item from decision tree
// compute profit of all children of extracted item
// and keep saving maxProfit
int maxProfit = 0;
while (!Q.empty())
{
// Dequeue a node
u = Q.front();
Q.pop();
// If it is starting node, assign level 0
if (u.level == -1)
v.level = 0;
// If there is nothing on next level
if (u.level == n-1)
continue;
// Else if not last node, then increment level,
// and compute profit of children nodes.
v.level = u.level + 1;
// Taking current level's item add current
// level's weight and value to node u's
// weight and value
v.weight = u.weight + arr[v.level].weight;
v.profit = u.profit + arr[v.level].value;
// If cumulated weight is less than W and
// profit is greater than previous profit,
// update maxprofit
if (v.weight <= W && v.profit > maxProfit)
maxProfit = v.profit;
// Get the upper bound on profit to decide
// whether to add v to Q or not.
v.bound = bound(v, n, W, arr);
// If bound value is greater than profit,
// then only push into queue for further
// consideration
if (v.bound > maxProfit)
Q.push(v);
// Do the same thing, but Without taking
// the item in knapsack
v.weight = u.weight;
v.profit = u.profit;
v.bound = bound(v, n, W, arr);
if (v.bound > maxProfit)
Q.push(v);
}
for(i=0;i<n;i++){
fprintf(bbdfs,"%d ,",checked[i]);
}
fprintf(bbdfs,"\n");
return maxProfit;
}