hdu4501(三维背包)

思路：dp[i][j][k]，第一维表示用钱买，第二维表示用积分换，第三维表示免费的。对于每个商品而言，要么用钱，要么用积分，要么用免费的次数。

所以呢，dp[i][j][k] = max(dp[i - a[s]][j][k],dp[i][j - b[s]][k],dp[i][j][k - 1]) + v[s];这个是对于地s个物品而言的。

/*****************************************
Author      :Crazy_AC(JamesQi)
Time        :2015
File Name   :
*****************************************/
// #pragma comment(linker, "/STACK:1024000000,1024000000")
#include <iostream>
#include <algorithm>
#include <iomanip>
#include <sstream>
#include <string>
#include <stack>
#include <queue>
#include <deque>
#include <vector>
#include <map>
#include <set>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <limits.h>
using namespace std;
#define MEM(a,b) memset(a,b,sizeof a)
typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int,int> ii;
const int inf = 1 << 30;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;
inline int Readint(){
char c = getchar();
while(!isdigit(c)) c = getchar();
int x = 0;
while(isdigit(c)){
x = x * 10 + c - '0';
c = getchar();
}
return x;
}
const int maxn = 110;
int dp[110][110][6];//qian,jifen,mianfei
int a[maxn],b[maxn],v[maxn];
int n,v1,v2,k;
int main()
{
// freopen("in.txt","r",stdin);
// freopen("out.txt","w",stdout);
while(~scanf("%d%d%d%d",&n,&v1,&v2,&k)){
for (int i = 0;i < n;i++)
scanf("%d%d%d",&a[i],&b[i],&v[i]);
memset(dp, 0,sizeof dp);
int ans = 0;
for (int i = 0;i < n;i++){
for (int x1 = v1;x1 >= 0;x1--){
for (int x2 = v2;x2 >= 0;x2--){
for (int x3 = k;x3 >= 0;x3--){
int tmp = 0;
if (x1 >= a[i]) tmp = max(tmp,dp[x1 - a[i]][x2][x3] + v[i]);
if (x2 >= b[i]) tmp = max(tmp,dp[x1][x2 - b[i]][x3] + v[i]);
if (x3 > 0) tmp = max(tmp,dp[x1][x2][x3 - 1] + v[i]);
// ans = max(ans,dp[x1][x2][x3]);
dp[x1][x2][x3] = max(dp[x1][x2][x3],tmp);
}
}
}
}
// cout << "ans = " << ans << '\n';
printf("%d\n",dp[v1][v2][k]);
}
return 0;
}