UVA 1598 Exchange

题目链接：https://vjudge.net/problem/UVA-1598

题目大意

　　翻译：https://blog.csdn.net/super_son/article/details/78162653

分析

　　巨烦的模拟题，debug一天。。。

　　要点：

1. 由于交易量可以取到 99999，所以交易量上限设 100000 比较好。
2. 每次交易只可以交易一个条目，不能多个条目合并在一起交易。
3. CANCEL 语句会有重复。
4. 如果来的是 SELL 条目，就是卖方主动；如果来的是 BUY 条目，就是买方主动。会影响实际售价。

代码如下

#include <bits/stdc++.h>
using namespace std;
 
#define INIT() ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
#define Rep(i,n) for (int i = 0; i < (int)(n); ++i)
#define For(i,s,t) for (int i = (int)(s); i <= (int)(t); ++i)
#define rFor(i,t,s) for (int i = (int)(t); i >= (int)(s); --i)
#define ForLL(i, s, t) for (LL i = LL(s); i <= LL(t); ++i)
#define rForLL(i, t, s) for (LL i = LL(t); i >= LL(s); --i)
#define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i)
#define rforeach(i,c) for (__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); ++i)
 
#define pr(x) cout << #x << " = " << x << "  "
#define prln(x) cout << #x << " = " << x << endl
 
#define LOWBIT(x) ((x)&(-x))
 
#define ALL(x) x.begin(),x.end()
#define INS(x) inserter(x,x.begin())
#define UNIQUE(x) x.erase(unique(x.begin(), x.end()), x.end())
#define REMOVE(x, c) x.erase(remove(x.begin(), x.end(), c), x.end()); // 删去 x 中所有 c 
#define TOLOWER(x) transform(x.begin(), x.end(), x.begin(),::tolower);
#define TOUPPER(x) transform(x.begin(), x.end(), x.begin(),::toupper);
 
#define ms0(a) memset(a,0,sizeof(a))
#define msI(a) memset(a,0x3f,sizeof(a))
#define msM(a) memset(a,-1,sizeof(a))

#define MP make_pair
#define PB push_back
#define ft first
#define sd second
 
template<typename T1, typename T2>
istream &operator>>(istream &in, pair<T1, T2> &p) {
    in >> p.first >> p.second;
    return in;
}
 
template<typename T>
istream &operator>>(istream &in, vector<T> &v) {
    for (auto &x: v)
        in >> x;
    return in;
}

template<typename T>
ostream &operator<<(ostream &out, vector<T> &v) {
    Rep(i, v.size()) out << v[i] << " 
"[i == v.size() - 1];
    return out;
}
 
template<typename T1, typename T2>
ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) {
    out << "[" << p.first << ", " << p.second << "]" << "
";
    return out;
}

inline int gc(){
    static const int BUF = 1e7;
    static char buf[BUF], *bg = buf + BUF, *ed = bg;
    
    if(bg == ed) fread(bg = buf, 1, BUF, stdin);
    return *bg++;
} 

inline int ri(){
    int x = 0, f = 1, c = gc();
    for(; c<48||c>57; f = c=='-'?-1:f, c=gc());
    for(; c>47&&c<58; x = x*10 + c - 48, c=gc());
    return x*f;
}

template<class T>
inline string toString(T x) {
    ostringstream sout;
    sout << x;
    return sout.str();
}

inline int toInt(string s) {
    int v;
    istringstream sin(s);
    sin >> v;
    return v;
}

//min <= aim <= max
template<typename T>
inline bool BETWEEN(const T aim, const T min, const T max) {
    return min <= aim && aim <= max;
}

typedef unsigned int uI;
typedef long long LL;
typedef unsigned long long uLL;
typedef vector< int > VI;
typedef vector< bool > VB;
typedef vector< char > VC;
typedef vector< double > VD;
typedef vector< string > VS;
typedef vector< LL > VL;
typedef vector< VI > VVI;
typedef vector< VB > VVB;
typedef vector< VS > VVS;
typedef vector< VL > VVL;
typedef vector< VVI > VVVI;
typedef vector< VVL > VVVL;
typedef pair< int, int > PII;
typedef pair< LL, LL > PLL;
typedef pair< int, string > PIS;
typedef pair< string, int > PSI;
typedef pair< string, string > PSS;
typedef pair< double, double > PDD;
typedef vector< PII > VPII;
typedef vector< PLL > VPLL;
typedef vector< VPII > VVPII;
typedef vector< VPLL > VVPLL;
typedef vector< VS > VVS;
typedef map< int, int > MII;
typedef unordered_map< int, int > uMII;
typedef map< LL, LL > MLL;
typedef map< string, int > MSI;
typedef map< int, string > MIS;
typedef multiset< int > mSI;
typedef set< int > SI;
typedef stack< int > SKI;
typedef deque< int > DQI;
typedef queue< int > QI;
typedef priority_queue< int > PQIMax;
typedef priority_queue< int, VI, greater< int > > PQIMin;
const double EPS = 1e-8;
const LL inf = 0x7fffffff;
const LL infLL = 0x7fffffffffffffffLL;
const LL mod = 1e9 + 7;
const int maxN = 1e4 + 7;
const LL ONE = 1;
const LL evenBits = 0xaaaaaaaaaaaaaaaa;
const LL oddBits = 0x5555555555555555;

struct Order {
    int id;
    int price;
    int num;
    
    Order(int x, int y, int z) {
        id = x;
        num = y;
        price = z;
    }
};

int N, T; 
vector< Order > orders; // 存放指令 
uMII orderMap; // 指令序号->数组下标，序号唯一 

struct BuyOrderCompare {
    bool operator() (int x, int y) {
        //assert(orderMap.find(x) != orderMap.end());
        //assert(orderMap.find(y) != orderMap.end());
        Order &X = orders[orderMap[x]];
        Order &Y = orders[orderMap[y]];
        
        return X.price > Y.price || X.price == Y.price && x < y;
    }
};

struct SellOrderCompare {
    bool operator() (int x, int y) {
        //assert(orderMap.find(x) != orderMap.end());
        //assert(orderMap.find(y) != orderMap.end());
        Order &X = orders[orderMap[x]];
        Order &Y = orders[orderMap[y]];
        
        return X.price < Y.price || X.price == Y.price && x < y;
    }
};

set< int, BuyOrderCompare > buyQueue;     // 购买队列 
set< int, SellOrderCompare > sellQueue;   // 售卖队列 
map< int, int, greater< int > > maxBuy;   // key为价格，value为对应数量，设这两个map是为了方便输出Quote 
MII minSell;

void init() {
    orders.clear();
    orders.PB(Order(-1, 0, 0));
    orders.PB(Order(-2, 0, 100000));
    
    orderMap.clear();
    orderMap[-1] = 0;
    orderMap[-2] = 1;
    
    buyQueue.clear();
    buyQueue.insert(-1);
    sellQueue.clear();
    sellQueue.insert(-2);
    
    maxBuy.clear();
    maxBuy[0] = 0;
    minSell.clear();
    minSell[100000] = 0;
}

void cancel(int x) {
    //assert(x != -1 && x != -2);
    if(orderMap.find(x) != orderMap.end()) {
        auto &X = orders[orderMap[x]];
        
        if(buyQueue.find(x) != buyQueue.end()) {
            maxBuy[X.price] -= X.num;
            if(!maxBuy[X.price]) maxBuy.erase(X.price); // 删掉后如果 X.price 所对应的数量为0，则删去X.price 
            
            buyQueue.erase(x);
        }
        else {
            minSell[X.price] -= X.num;
            if(!minSell[X.price]) minSell.erase(X.price);
            
            sellQueue.erase(x);
        }
        orderMap.erase(x); // 这个要最后删 
    }
}

bool Trade(bool isbuy) {
    PII ret(0, 0);
    Order &X = orders[orderMap[*buyQueue.begin()]];
    Order &Y = orders[orderMap[*sellQueue.begin()]];
    
    if(!X.num || !Y.num || X.price < Y.price) return false;
    
    if(!isbuy) ret.sd = X.price;
    else ret.sd = Y.price;
    ret.ft = min(X.num, Y.num);
    
    if(X.num > Y.num) {
        X.num -= Y.num;
        maxBuy[X.price] -= Y.num; // 更新 
        cancel(Y.id);             // 没货了可以删掉，不影响答案 
    }
    else if(X.num < Y.num) {
        Y.num -= X.num;
        minSell[Y.price] -= X.num; // 更新 
        cancel(X.id);              // 没货了可以删掉，不影响答案 
    }
    else {
        cancel(X.id);
        cancel(Y.id);
    }
    
    printf("TRADE %d %d
", ret.ft, ret.sd);
    return true;
}

void printQuote() {
    auto itBuy = maxBuy.begin();
    auto itSell = minSell.begin();
    //assert(itBuy != maxBuy.end() && itSell != minSell.end());
    printf("QUOTE %d %d - %d %d
", itBuy->sd, itBuy->ft, itSell->sd, itSell->ft == 100000 ? itSell->ft - 1 : itSell->ft);
}

int main() {
    //freopen("MyOutput.txt","w",stdout);
    //freopen("input.txt","r",stdin);
    //INIT();
    char ch[6];
    while(~scanf("%d", &N)) {
        if(T++) cout << endl;
        init(); // 初始化 
        For(i, 1, N) {
            scanf("%s", ch);
            if(ch[0] == 'B') {
                int sz, price;
                scanf("%d%d", &sz, &price);
                
                orders.PB(Order(i, sz, price));
                orderMap[i] = orders.size() - 1;
                buyQueue.insert(i);
                
                maxBuy[price] += sz;
                
                while(Trade(true)) ;
                
                printQuote();
            }
            else if(ch[0] == 'S') {
                int sz, price;
                scanf("%d%d", &sz, &price);
                
                orders.PB(Order(i, sz, price));
                orderMap[i] = orders.size() - 1;
                sellQueue.insert(i);
                
                minSell[price] += sz;
                
                while(Trade(false)) ;
                
                printQuote();
            }
            else {
                int id;
                scanf("%d", &id);
                
                cancel(id);
                
                printQuote();
            }
        }
    }
    return 0;
}