POJ 1789 Truck History

阳光穿透心脏的1/2处 2021-11-01 06:18 211阅读 0赞

题目链接：[https://vjudge.net/problem/POJ-1789][https_vjudge.net_problem_POJ-1789]

### 题目大意 ###

给定 N 辆车的车牌号，每个车牌号由 7 个字母组成，每个车牌号都可以由另一个车牌号衍生而来，代价为两字符串具有不同的字符的位置数。现在要你构造一个衍生网络，使得车牌衍生总代价最小。

### 分析 ###

最小生成树模板题，由于此图为稠密图，应用 Prim 算法。

### 代码如下 ###

![ContractedBlock.gif][] ![ExpandedBlockStart.gif][]

1 #include <cmath>
      2 #include <ctime>
      3 #include <iostream>
      4 #include <string>
      5 #include <vector>
      6 #include <cstdio>
      7 #include <cstdlib>
      8 #include <cstring>
      9 #include <queue>
     10 #include <map>
     11 #include <set>
     12 #include <algorithm>
     13 #include <cctype>
     14 #include <stack>
     15 #include <deque>
     16 #include <list>
     17 #include <sstream>
     18 #include <cassert>
     19 using namespace std;
     20  
     21 #define INIT() ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
     22 #define Rep(i,n) for (int i = 0; i < (n); ++i)
     23 #define For(i,s,t) for (int i = (s); i <= (t); ++i)
     24 #define rFor(i,t,s) for (int i = (t); i >= (s); --i)
     25 #define ForLL(i, s, t) for (LL i = LL(s); i <= LL(t); ++i)
     26 #define rForLL(i, t, s) for (LL i = LL(t); i >= LL(s); --i)
     27 #define foreach(i,c) for (__typeof(c.begin()) i = c.begin(); i != c.end(); ++i)
     28 #define rforeach(i,c) for (__typeof(c.rbegin()) i = c.rbegin(); i != c.rend(); ++i)
     29  
     30 #define pr(x) cout << #x << " = " << x << "  "
     31 #define prln(x) cout << #x << " = " << x << endl
     32  
     33 #define LOWBIT(x) ((x)&(-x))
     34  
     35 #define ALL(x) x.begin(),x.end()
     36 #define INS(x) inserter(x,x.begin())
     37 #define UNIQUE(x) x.erase(unique(x.begin(), x.end()), x.end())
     38 #define REMOVE(x, c) x.erase(remove(x.begin(), x.end(), c), x.end()); // 删去 x 中所有 c 
     39 #define TOLOWER(x) transform(x.begin(), x.end(), x.begin(),::tolower);
     40 #define TOUPPER(x) transform(x.begin(), x.end(), x.begin(),::toupper);
     41  
     42 #define ms0(a) memset(a,0,sizeof(a))
     43 #define msI(a) memset(a,0x3f,sizeof(a))
     44 #define msM(a) memset(a,-1,sizeof(a))
     45 
     46 #define MP make_pair
     47 #define PB push_back
     48 #define ft first
     49 #define sd second
     50  
     51 template<typename T1, typename T2>
     52 istream &operator>>(istream &in, pair<T1, T2> &p) {
     53     in >> p.first >> p.second;
     54     return in;
     55 }
     56  
     57 template<typename T>
     58 istream &operator>>(istream &in, vector<T> &v) {
     59     for (auto &x: v)
     60         in >> x;
     61     return in;
     62 }
     63  
     64 template<typename T1, typename T2>
     65 ostream &operator<<(ostream &out, const std::pair<T1, T2> &p) {
     66     out << "[" << p.first << ", " << p.second << "]" << "\n";
     67     return out;
     68 }
     69 
     70 inline int gc(){
     71     static const int BUF = 1e7;
     72     static char buf[BUF], *bg = buf + BUF, *ed = bg;
     73     
     74     if(bg == ed) fread(bg = buf, 1, BUF, stdin);
     75     return *bg++;
     76 } 
     77 
     78 inline int ri(){
     79     int x = 0, f = 1, c = gc();
     80     for(; c<48||c>57; f = c=='-'?-1:f, c=gc());
     81     for(; c>47&&c<58; x = x*10 + c - 48, c=gc());
     82     return x*f;
     83 }
     84 
     85 template<class T>
     86 inline string toString(T x) {
     87     ostringstream sout;
     88     sout << x;
     89     return sout.str();
     90 }
     91 
     92 inline int toInt(string s) {
     93     int v;
     94     istringstream sin(s);
     95     sin >> v;
     96     return v;
     97 }
     98 
     99 //min <= aim <= max
    100 template<typename T>
    101 inline bool BETWEEN(const T aim, const T min, const T max) {
    102     return min <= aim && aim <= max;
    103 }
    104  
    105 typedef long long LL;
    106 typedef unsigned long long uLL;
    107 typedef pair< double, double > PDD;
    108 typedef pair< int, int > PII;
    109 typedef pair< int, PII > PIPII;
    110 typedef pair< string, int > PSI;
    111 typedef pair< int, PSI > PIPSI;
    112 typedef set< int > SI;
    113 typedef set< PII > SPII;
    114 typedef vector< int > VI;
    115 typedef vector< double > VD;
    116 typedef vector< VI > VVI;
    117 typedef vector< SI > VSI;
    118 typedef vector< PII > VPII;
    119 typedef map< int, int > MII;
    120 typedef map< LL, int > MLLI;
    121 typedef map< int, string > MIS;
    122 typedef map< int, PII > MIPII;
    123 typedef map< PII, int > MPIII;
    124 typedef map< string, int > MSI;
    125 typedef map< string, string > MSS;
    126 typedef map< PII, string > MPIIS;
    127 typedef map< PII, PII > MPIIPII;
    128 typedef multimap< int, int > MMII;
    129 typedef multimap< string, int > MMSI;
    130 //typedef unordered_map< int, int > uMII;
    131 typedef pair< LL, LL > PLL;
    132 typedef vector< LL > VL;
    133 typedef vector< VL > VVL;
    134 typedef priority_queue< int > PQIMax;
    135 typedef priority_queue< int, VI, greater< int > > PQIMin;
    136 const double EPS = 1e-8;
    137 const LL inf = 0x3fffffff;
    138 const LL infLL = 0x3fffffffffffffffLL;
    139 const LL mod = 1e9 + 7;
    140 const int maxN = 2e3 + 7;
    141 const LL ONE = 1;
    142 const LL evenBits = 0xaaaaaaaaaaaaaaaa;
    143 const LL oddBits = 0x5555555555555555;
    144 
    145 int N, M, ans;
    146 int adj[maxN][maxN], dist[maxN];
    147 string truck[maxN];
    148 bool vis[maxN];
    149 
    150 int calDist(string &s1, string &s2) {
    151     int ret = 0;
    152     Rep(i, s1.size()) if(s1[i] != s2[i]) ++ret;
    153     return ret;
    154 }
    155 
    156 void Prim(int S) {
    157     ms0(vis);
    158     vis[S] = 1;
    159     For(i, 1, N) dist[i] = adj[S][i];
    160     
    161     Rep(cnt, N - 1) {
    162         int index, minW = inf;
    163         
    164         For(i, 1, N) {
    165             if(!vis[i] && minW > dist[i]) {
    166                 index = i;
    167                 minW = dist[i];
    168             }
    169         }
    170         
    171         ans += minW;
    172         vis[index] = 1;
    173         
    174         For(i, 1, N) if(!vis[i] && dist[i] > adj[index][i]) dist[i] = adj[index][i];
    175     }
    176 }
    177 
    178 int main(){
    179     //freopen("MyOutput.txt","w",stdout);
    180     //freopen("input.txt","r",stdin);
    181     INIT();
    182     while(cin >> N && N) {
    183         ans = 0;
    184         For(i, 1, N) cin >> truck[i];
    185         For(i, 1, N) {
    186             For(j, i + 1, N) {
    187                 adj[i][j] = adj[j][i] = calDist(truck[i], truck[j]);
    188             }
    189         }
    190         
    191         Prim(1);
    192         if(ans == 1) cout << "The highest possible quality is 1." << endl;
    193         else cout << "The highest possible quality is 1/" << ans << ".\n";
    194     }
    195     return 0;
    196 }

转载于:https://www.cnblogs.com/zaq19970105/p/11303103.html

[https_vjudge.net_problem_POJ-1789]: https://vjudge.net/problem/POJ-1789
[ContractedBlock.gif]: https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif
[ExpandedBlockStart.gif]: /images/20211101/76dfa74ead1243a583858f0a99b7d53a.png