POJ - 2392 Space Elevator 多重背包

传送门：POJ2392

题意：有k种砖头，每种高为hi，可以摞到的最大高度为ai，数量为ci，问用这些砖头最多摞多高。

思路：典型多重背包，算了算感觉不加优化也能过，写一发还真过了。。

暴力：

#include
#include
#define ll long long
#define pb push_back
#define fi first
#define se second
#define pi acos(-1)
#define inf 0x3f3f3f3f
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define rep(i,x,n) for(int i=x;i=x;i--)
using namespace std;
typedef pairP;
const int MAXN=100010;
int gcd(int a,int b){return b?gcd(b,a%b):a;}
bool dp[50000];
struct node{
	int h, a, c;
	bool operator < (node x) const
	{
		return a < x.a;
	}
}p[MAXN];
int main()
{
	int n;
	cin >> n;
	for(int i = 0; i < n; i++)
	cin >> p[i].h >> p[i].a >> p[i].c;
	sort(p, p + n);
	dp[0] = 1;
	for(int i = 0; i < n; i++)
	{
		for(int j = p[i].a; j >=p[i].h; j--)
		{
			for(int k = 1; k <= p[i].c && k * p[i].h <= j; k++)
			{
				dp[j] |= dp[j - k * p[i].h];
			}
		}
	}
	for(int i = 40000; i >= 0; i--)
	if(dp[i])
	{
		cout << i << endl;
		return 0;
	 } 
 	return 0;
}

二进制优化：

#include
#include
#define ll long long
#define pb push_back
#define fi first
#define se second
#define pi acos(-1)
#define inf 0x3f3f3f3f
#define lson l,mid,rt<<1
#define rson mid+1,r,rt<<1|1
#define rep(i,x,n) for(int i=x;i=x;i--)
using namespace std;
typedef pairP;
const int MAXN=100010;
int gcd(int a,int b){return b?gcd(b,a%b):a;}
bool dp[50000];
struct node{
	int h, a, c;
	bool operator < (node x) const
	{
		return a < x.a;
	}
}p[MAXN];
int V;
void zero(int cost)
{
	for(int i=V;i>=cost;i--)
	dp[i] |= dp[i-cost];
}
void complet(int cost)
{
	for(int i=cost;i<=V;i++)
	dp[i] |= dp[i-cost];
}
void multi(int cost ,int amount)
{
   	if(cost*amount>=V)
   	{
	   	complet(cost);
	   	return;
	   }
	   int k=1;
	   while(k> n;
	for(int i = 0; i < n; i++)
	cin >> p[i].h >> p[i].a >> p[i].c;
	sort(p, p + n);
	dp[0] = 1;
	for(int i = 0; i < n; i++)
	V = p[i].a, multi(p[i].h, p[i].c);
	for(int i = 40000; i >= 0; i--)
	if(dp[i])
	{
		cout << i << endl;
		return 0;
	 } 
 	return 0;
}