题目链接：https://vjudge.net/problem/POJ-1287
1 #include 2 #include 3 #include 4 #include <string> 5 #include 6 #include 7 #include 8 #include 9 #include 10 #include 11 #include <set> 12 #include 13 #include 14 #include 15 #include 16 #include 17 #include 18 #include 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 52 istream &operator>>(istream &in, pair &p) { 53 in >> p.first >> p.second; 54 return in; 55 } 56 57 template 58 istream &operator>>(istream &in, vector &v) { 59 for (auto &x: v) 60 in >> x; 61 return in; 62 } 63 64 template 65 ostream &operator<<(ostream &out, const std::pair &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 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 = 5e1 + 7; 141 const LL ONE = 1; 142 const LL evenBits = 0xaaaaaaaaaaaaaaaa; 143 const LL oddBits = 0x5555555555555555; 144 145 struct Edge{ 146 int from, to, w; 147 148 inline bool operator< (const Edge &x) const { 149 return w < x.w; 150 } 151 }; 152 153 istream& operator>> (istream &in, Edge &x) { 154 in >> x.from >> x.to >> x.w; 155 return in; 156 } 157 158 int N, M, ans; 159 vector< Edge > E; 160 161 // 并查集 162 int f[maxN]; 163 164 inline int Find(int x) { 165 while(x != f[x]) x = f[x] = f[f[x]]; 166 return x; 167 } 168 169 inline void Union(int x, int y) { 170 f[y] = f[x]; 171 } 172 173 void init() { 174 For(i, 1, N) f[i] = i; 175 E.clear(); 176 177 ans = 0; 178 } 179 180 void Kruskal() { 181 int cnt = 1; 182 sort(ALL(E)); 183 184 Rep(i, E.size()) { 185 if(cnt >= N) break; 186 int x = Find(E[i].from), y = Find(E[i].to); 187 188 if(x != y) { 189 ++cnt; 190 Union(x, y); 191 ans += E[i].w; 192 } 193 } 194 } 195 196 int main(){ 197 //freopen("MyOutput.txt","w",stdout); 198 //freopen("input.txt","r",stdin); 199 INIT(); 200 while(cin >> N && N) { 201 init(); 202 cin >> M; 203 For(i, 1, M) { 204 Edge t; 205 cin >> t; 206 E.PB(t); 207 } 208 209 Kruskal(); 210 211 cout << ans << endl; 212 } 213 return 0; 214 }
转载于:https://www.cnblogs.com/zaq19970105/p/11302374.html
