UVA 12108 Extraordinarily Tired Students

Posted 2022-01-20 zaq19970105

题目链接：https://vjudge.net/problem/UVA-12108

题目翻译摘自《算法禁赛入门经典》

题目大意

　　课堂上有 n 个学生（n ≤ 10）。每个学生都有一个“睡眠-清醒”周期，其中第 i 个学生醒 A_i 分 钟后睡 B_i 分钟，然后重复（1 ≤ A_i，B_i ≤ 5），初始时第 i 个学生处在他的周期的第 C_i 分钟。每个 学生在临睡前会察看全班睡觉人数是否严格大于清醒人数，只有这个条件满足时才睡觉，否 则就坚持听课 A_i 分钟后再次检查这个条件。问经过多长时间后全班都清醒。

　　注意：有可能并不存在“全部都清醒”的时刻，此时应输出-1。

分析

　　一分钟一分钟模拟，并用个集合储存状态，有重复状态出现说明不存在。

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 << "]" << "\n";
 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< PII > VPII;
 83 typedef map< int, int > MII;
 84 typedef map< int, string > MIS;
 85 typedef map< int, PII > MIPII;
 86 typedef map< PII, int > MPIII;
 87 typedef map< string, int > MSI;
 88 typedef map< string, string > MSS;
 89 typedef map< PII, string > MPIIS;
 90 typedef map< PII, PII > MPIIPII;
 91 typedef multimap< int, int > MMII;
 92 typedef multimap< string, int > MMSI;
 93 //typedef unordered_map< int, int > uMII;
 94 typedef pair< LL, LL > PLL;
 95 typedef vector< LL > VL;
 96 typedef vector< VL > VVL;
 97 typedef priority_queue< int > PQIMax;
 98 typedef priority_queue< int, VI, greater< int > > PQIMin;
 99 const double EPS = 1e-6;
100 const LL inf = 0x7fffffff;
101 const LL infLL = 0x7fffffffffffffffLL;
102 const LL mod = 1e9 + 7;
103 const int maxN = 1e3 + 7;
104 const LL ONE = 1;
105 const LL evenBits = 0xaaaaaaaaaaaaaaaa;
106 const LL oddBits = 0x5555555555555555;
107 
108 int n, T, ans;
109 int a[11], b[11], c[11];
110 
111 int main()
112     //freopen("MyOutput.txt","w",stdout);
113     //freopen("input.txt","r",stdin);
114     //INIT();
115     while(cin >> n) 
116         if(!n) break;
117         set< string > state;
118         
119         ans = 0;
120         Rep(i, n) cin >> a[i] >> b[i] >> c[i];
121         
122         while(++ans) 
123             int cnt = 0, remain = 0;
124             string tmp;
125             
126             Rep(i, n) 
127                 int t = (ans + c[i] - 2) % (a[i] + b[i]) + 1;
128                 if(t <= a[i]) ++cnt;
129                 else remain = max(a[i] + b[i] - t + 1, remain);
130                 tmp.PB(t + ‘0‘); 
131             
132             
133             if(cnt >= (n + 1) / 2) 
134                 ans += remain;
135                 break;
136             
137             else 
138                 if(state.find(tmp) != state.end()) 
139                     ans = -1;
140                     break;
141                 
142                 else state.insert(tmp);
143             
144         
145         
146         printf("Case %d: %d\n", ++T, ans);
147     
148     return 0;
149 

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