题目链接:https://vjudge.net/problem/UVA-540
题目翻译摘自《算法禁赛入门经典》
题目大意
有 t 个团队的人正在排一个长队。每次新来一个人时,如果他有队友在排队,那么这个新人会插队到最后一个队友的身后。如果没有任何一个队友排队,则他会排到长队的队尾。 输入每个团队中所有队员的编号,要求支持如下3种指令(前两种指令可以穿插进行)。
- ENQUEUEx:编号为 x 的人进入长队。
- DEQUEUE:长队的队首出队。
- STOP:停止模拟。
对于每个DEQUEUE指令,输出出队的人的编号。
分析
嵌套队列。
代码如下
1 #include <bits/stdc++.h> 2 using namespace std; 3 4 #define INIT() ios::sync_with_stdio(false);cin.tie(0);cout.tie(0); 5 #define Rep(i,n) for (int i = 0; i < (n); ++i) 6 #define For(i,s,t) for (int i = (s); i <= (t); ++i) 7 #define rFor(i,t,s) for (int i = (t); i >= (s); --i) 8 #define ForLL(i, s, t) for (LL i = LL(s); i <= LL(t); ++i) 9 #define rForLL(i, t, s) for (LL i = LL(t); i >= LL(s); --i) 10 #define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i) 11 #define rforeach(i,c) for (__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); ++i) 12 13 #define pr(x) cout << #x << " = " << x << " " 14 #define prln(x) cout << #x << " = " << x << endl 15 16 #define LOWBIT(x) ((x)&(-x)) 17 18 #define ALL(x) x.begin(),x.end() 19 #define INS(x) inserter(x,x.begin()) 20 21 #define ms0(a) memset(a,0,sizeof(a)) 22 #define msI(a) memset(a,inf,sizeof(a)) 23 #define msM(a) memset(a,-1,sizeof(a)) 24 25 #define MP make_pair 26 #define PB push_back 27 #define ft first 28 #define sd second 29 30 template<typename T1, typename T2> 31 istream &operator>>(istream &in, pair<T1, T2> &p) { 32 in >> p.first >> p.second; 33 return in; 34 } 35 36 template<typename T> 37 istream &operator>>(istream &in, vector<T> &v) { 38 for (auto &x: v) 39 in >> x; 40 return in; 41 } 42 43 template<typename T1, typename T2> 44 ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) { 45 out << "[" << p.first << ", " << p.second << "]" << " "; 46 return out; 47 } 48 49 inline int gc(){ 50 static const int BUF = 1e7; 51 static char buf[BUF], *bg = buf + BUF, *ed = bg; 52 53 if(bg == ed) fread(bg = buf, 1, BUF, stdin); 54 return *bg++; 55 } 56 57 inline int ri(){ 58 int x = 0, f = 1, c = gc(); 59 for(; c<48||c>57; f = c=='-'?-1:f, c=gc()); 60 for(; c>47&&c<58; x = x*10 + c - 48, c=gc()); 61 return x*f; 62 } 63 64 template<class T> 65 inline string toString(T x) { 66 ostringstream sout; 67 sout << x; 68 return sout.str(); 69 } 70 71 typedef long long LL; 72 typedef unsigned long long uLL; 73 typedef pair< double, double > PDD; 74 typedef pair< int, int > PII; 75 typedef pair< int, PII > PIPII; 76 typedef pair< string, int > PSI; 77 typedef pair< int, PSI > PIPSI; 78 typedef set< int > SI; 79 typedef set< PII > SPII; 80 typedef vector< int > VI; 81 typedef vector< VI > VVI; 82 typedef vector< SI > VSI; 83 typedef vector< PII > VPII; 84 typedef map< int, int > MII; 85 typedef map< int, string > MIS; 86 typedef map< int, PII > MIPII; 87 typedef map< PII, int > MPIII; 88 typedef map< string, int > MSI; 89 typedef map< string, string > MSS; 90 typedef map< PII, string > MPIIS; 91 typedef map< PII, PII > MPIIPII; 92 typedef multimap< int, int > MMII; 93 typedef multimap< string, int > MMSI; 94 //typedef unordered_map< int, int > uMII; 95 typedef pair< LL, LL > PLL; 96 typedef vector< LL > VL; 97 typedef vector< VL > VVL; 98 typedef priority_queue< int > PQIMax; 99 typedef priority_queue< int, VI, greater< int > > PQIMin; 100 const double EPS = 1e-10; 101 const LL inf = 0x7fffffff; 102 const LL infLL = 0x7fffffffffffffffLL; 103 const LL mod = 1e9 + 7; 104 const int maxN = 1e3 + 7; 105 const LL ONE = 1; 106 const LL evenBits = 0xaaaaaaaaaaaaaaaa; 107 const LL oddBits = 0x5555555555555555; 108 109 int T, t; 110 string op; 111 112 int main(){ 113 //freopen("MyOutput.txt","w",stdout); 114 //freopen("input.txt","r",stdin); 115 //INIT(); 116 while(cin >> t) { 117 if(!t) break; 118 MII mii; // stu_id->team_id 119 queue< int > Q; 120 queue< int > team[t + 1]; 121 int vis[t + 1]; // 标识某队伍在不在大队列中 122 ms0(vis); 123 124 For(i, 1, t) { 125 int x, y; 126 cin >> x; 127 Rep(j, x) { 128 cin >> y; 129 mii[y] = i; 130 } 131 } 132 133 printf("Scenario #%d ", ++T); 134 while(cin >> op) { 135 if(op == "STOP") break; 136 if(op[0] == 'E') { 137 int x, y; 138 cin >> x; 139 y = mii[x]; 140 team[y].push(x); 141 if(!vis[y]) { 142 vis[y] = 1; 143 Q.push(y); 144 } 145 } 146 else { 147 int x = Q.front(); 148 cout << team[x].front() << endl; 149 team[x].pop(); 150 if(team[x].empty()) { 151 vis[x] = 0; 152 Q.pop(); 153 } 154 } 155 } 156 cout << endl; 157 } 158 return 0; 159 }