Fund Management UVA - 1412 

很有难度的一道题

将n元组映射成一个数字，既方便了状态的转移，也加快了时间，否则利用九进制去进行操作，很麻烦的

将所有状态都记录下来之后，股票的买个卖就可以抽象成一幅图了，也方便了状态转移

具体细节看代码吧

#include<iostream>
#include<cmath>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<iomanip>
#include<assert.h>
#include<vector>
#include<list>
#include<map>
#include<set>
#include<sstream>
#include<stack>
#include<queue>
#include<string>
#include<algorithm>
#pragma warning(disable:4996)
#define me(s)  memset(s,0,sizeof(s))
#define _for(i,a,b) for(int i=(a);i<(b);++i)
#define _rep(i,a,b) for(int i=(a);i<=(b);++i)
using namespace std;
typedef pair <int, int> pii;
typedef long long ll;
typedef unsigned long long llu;
const int MOD = 1e9 + 7;
const double pi = acos(-1.0);
const double eps = 1e-15;
const double INF = 1e30;
const int maxn = 8;
const int maxm = 100 + 5;
const int maxstate = 15000;

int m, n, s[maxn], k[maxn], kk;
double c, price[maxn][maxm];
char name[maxn][10];

double d[maxm][maxstate];
int opt[maxm][maxstate], pre[maxm][maxstate];

int buy_next[maxstate][maxn], sell_next[maxstate][maxn];
vector<vector<int> > states;
map<vector<int>, int> ID;

void dfs(int stock, vector<int>& lots, int totlot) {
	if (stock == n) {
		ID[lots] = states.size();
		states.push_back(lots);
	}
	else for (int i = 0; i <= k[stock] && totlot + i <= kk; i++) {
		lots[stock] = i;
		dfs(stock + 1, lots, totlot + i);
	}
}

void init() {
	vector<int> lots(n);
	states.clear();
	ID.clear();
	dfs(0, lots, 0);
	for (int s = 0; s < states.size(); s++) {
		int totlot = 0;
		for (int i = 0; i < n; i++) totlot += states[s][i];
		for (int i = 0; i < n; i++) {
			buy_next[s][i] = sell_next[s][i] = -1;
			if (states[s][i] < k[i] && totlot < kk) {
				vector<int> newstate = states[s];
				newstate[i]++;
				buy_next[s][i] = ID[newstate];
			}
			if (states[s][i] > 0) {
				vector<int> newstate = states[s];
				newstate[i]--;
				sell_next[s][i] = ID[newstate];
			}
		}
	}
}

void update(int day, int s, int s2, double v, int o) {
	if (v > d[day + 1][s2]) {
		d[day + 1][s2] = v;
		opt[day + 1][s2] = o;
		pre[day + 1][s2] = s;
	}
}

double dp() {
	for (int day = 0; day <= m; day++)
		for (int s = 0; s < states.size(); s++) d[day][s] = -INF;

	d[0][0] = c;
	for (int day = 0; day < m; day++)
		for (int s = 0; s < states.size(); s++) {
			double v = d[day][s];
			if (v < -1) continue;

			update(day, s, s, v, 0); // HOLD
			for (int i = 0; i < n; i++) {
				if (buy_next[s][i] >= 0 && v >= price[i][day] - 1e-3)
					update(day, s, buy_next[s][i], v - price[i][day], i + 1); // BUY
				if (sell_next[s][i] >= 0)
					update(day, s, sell_next[s][i], v + price[i][day], -i - 1); // SELL
			}
		}
	return d[m][0];
}

void print_ans(int day, int s) {
	if (day == 0) return;
	print_ans(day - 1, pre[day][s]);
	if (opt[day][s] == 0) printf("HOLD\n");
	else if (opt[day][s] > 0) printf("BUY %s\n", name[opt[day][s] - 1]);
	else printf("SELL %s\n", name[-opt[day][s] - 1]);
}

int main() {
	int kase = 0;
	while (scanf("%lf%d%d%d", &c, &m, &n, &kk) == 4) {
		if (kase++ > 0) printf("\n");

		for (int i = 0; i < n; i++) {
			scanf("%s%d%d", name[i], &s[i], &k[i]);
			for (int j = 0; j < m; j++) { scanf("%lf", &price[i][j]); price[i][j] *= s[i]; }
		}
		init();

		double ans = dp();
		printf("%.2lf\n", ans);
		print_ans(m, 0);
	}
	return 0;
}