5 升 3 升 容器，生成任何数量的水的算法实现

You have a five-quart jug, a three-quart jug, and an unlimited supply of water (but no measuring cups). How would you come up with exactly
four quarts of water? Note that the jugs are oddly shaped, such that filling up exactly "half" of the jug would be impossible.

算法不够优化，可以实现生成任何容量的水。 但是如果输入的水容量过大，会导致计算时间过程。

日后有时间，在考虑其他的实现，以及优化。放在这里，只是作为一个记录。

#include <iostream>
#include <stack>

using namespace std;

#define JUG_A   5
#define JUG_B   3

struct node
{
struct node * parent;
struct node * childs;
struct node * next;
int a;  /* jug a */
int b;  /* jug b */
int c; /* total of summary */

node (node* pNode)
{
a = pNode->a;
b = pNode->b;
c = pNode->c;
parent = pNode;
childs = NULL;
next = NULL;
}
node ()
{
parent = NULL;
childs = NULL;
next = NULL;

a = 0;
b = 0;
c = 0;
}
bool OK(int n) {
if(a == n || b == n || c == n
/*|| a+b == n || a + c == n || b + c == n*/)
{
return true;
}
return false;
}
};

void printNode(const node * pNode)
{
cout << " " << pNode->a << " " << pNode->b << " " << pNode->c << endl;
}
node *fillNode(node* pNode )
{
int t;
node * tmp;
/* fill up jug a */
node* pFillJugA  = new node(pNode);
pNode->childs = pFillJugA;
tmp = pFillJugA;
pFillJugA->a = JUG_A ;

/* fill up jug b */
node * pFillJugB = new node(pNode);
tmp->next = pFillJugB;
tmp = pFillJugB;
pFillJugB->b = JUG_B;

if(pNode->a > 0)
{
/* from jug a to b */
node *pFromAToB = new node(pNode);
tmp->next = pFromAToB ;
tmp = pFromAToB;
t = JUG_B - pFromAToB->b;
pFromAToB->a -= t;
pFromAToB->b += t;
}
if(pNode->b > 0)
{
/* from jug b to a */
node * pFromB2A = new node(pNode);
tmp->next = pFromB2A;
tmp = pFromB2A;
t = JUG_A - pFromB2A->a ;
t = t > pFromB2A->b ? pFromB2A->b : t;
pFromB2A->a += t;
pFromB2A->b -= t;
}
if(pNode->a > 0)
{
/* from a to c */
node * pFromA2C = new node(pNode);
tmp->next = pFromA2C;
tmp = pFromA2C;
pFromA2C->c += pFromA2C->a;
pFromA2C->a = 0;
}
if(pNode->b > 0)
{
/* from b to c */
node * pFromB2C = new node(pNode);
tmp->next = pFromB2C;
tmp = pFromB2C;
pFromB2C->c += pFromB2C->b;
pFromB2C->b = 0;
}
return pFillJugA;
}
void destroyNode(stack<node *> &sn)
{
node * first, *tmp;
while(!sn.empty())
{
first = sn.top();
sn.pop();
while(first)
{
tmp = first->next;
delete first;
first = tmp;
}
}
}
void search(int n)
{
stack<node *> sNode;
node * cur =  new node();
sNode.push(cur);
bool flag = false;
node * first , * tmp;

do
{
first = NULL;
cur = sNode.top();
while(cur)
{
if(cur->OK(n)) {flag =true; break;}
node * retnode = fillNode(cur);
if(first == NULL) { first = retnode;}
else {
tmp = first;
while(tmp->next)
{
tmp = tmp->next;
}
tmp->next = retnode;
}
cur = cur->next;
}
sNode.push(first);
} while(!flag);
stack<node*> outPutNode;
while(cur)
{
outPutNode.push(cur);
cur = cur->parent;
}

cout <<endl;
while(!outPutNode.empty())
{
printNode(outPutNode.top());
outPutNode.pop();
}
destroyNode(sNode);
}

int main()
{
int n ;
cout << endl<< "Please input the quart you want to get : " ;
while(cin >> n)
{
if(n <= 0) { break;}
search(n);
cout << endl << "Please input the quart you want to get : " ;
}

return 0;
}