formatting filenames d7af6fdc8c

graph/kruskal.cpp

@@ -0,0 +1,135 @@
+#include <iostream>
+//#include <boost/multiprecision/cpp_int.hpp>
+//using namespace boost::multiprecision;
+const int mx = 1e6 + 5;
+const long int inf = 2e9;
+typedef long long ll;
+#define rep(i, n) for (i = 0; i < n; i++)
+#define repp(i, a, b) for (i = a; i <= b; i++)
+#define pii pair<int, int>
+#define vpii vector<pii>
+#define vi vector<int>
+#define vll vector<ll>
+#define r(x) scanf("%d", &x)
+#define rs(s) scanf("%s", s)
+#define gc getchar_unlocked
+#define pc putchar_unlocked
+#define mp make_pair
+#define pb push_back
+#define lb lower_bound
+#define ub upper_bound
+#define endl "\n"
+#define fast                          \
+	ios_base::sync_with_stdio(false); \
+	cin.tie(NULL);                    \
+	cout.tie(NULL);
+using namespace std;
+void in(int &x)
+{
+	register int c = gc();
+	x = 0;
+	int neg = 0;
+	for (; ((c < 48 || c > 57) && c != '-'); c = gc())
+		;
+	if (c == '-')
+	{
+		neg = 1;
+		c = gc();
+	}
+	for (; c > 47 && c < 58; c = gc())
+	{
+		x = (x << 1) + (x << 3) + c - 48;
+	}
+	if (neg)
+		x = -x;
+}
+void out(int n)
+{
+	int N = n, rev, count = 0;
+	rev = N;
+	if (N == 0)
+	{
+		pc('0');
+		return;
+	}
+	while ((rev % 10) == 0)
+	{
+		count++;
+		rev /= 10;
+	}
+	rev = 0;
+	while (N != 0)
+	{
+		rev = (rev << 3) + (rev << 1) + N % 10;
+		N /= 10;
+	}
+	while (rev != 0)
+	{
+		pc(rev % 10 + '0');
+		rev /= 10;
+	}
+	while (count--)
+		pc('0');
+}
+ll parent[mx], arr[mx], node, edge;
+vector<pair<ll, pair<ll, ll>>> v;
+void initial()
+{
+	int i;
+	rep(i, node + edge)
+		parent[i] = i;
+}
+int root(int i)
+{
+	while (parent[i] != i)
+	{
+		parent[i] = parent[parent[i]];
+		i = parent[i];
+	}
+	return i;
+}
+void join(int x, int y)
+{
+	int root_x = root(x); //Disjoint set union by rank
+	int root_y = root(y);
+	parent[root_x] = root_y;
+}
+ll kruskal()
+{
+	ll mincost = 0, i, x, y;
+	rep(i, edge)
+	{
+		x = v[i].second.first;
+		y = v[i].second.second;
+		if (root(x) != root(y))
+		{
+			mincost += v[i].first;
+			join(x, y);
+		}
+	}
+	return mincost;
+}
+int main()
+{
+	fast;
+	while (1)
+	{
+		int i, j, from, to, cost, totalcost = 0;
+		cin >> node >> edge; //Enter the nodes and edges
+		if (node == 0 && edge == 0)
+			break; //Enter 0 0 to break out
+		initial(); //Initialise the parent array
+		rep(i, edge)
+		{
+			cin >> from >> to >> cost;
+			v.pb(mp(cost, mp(from, to)));
+			totalcost += cost;
+		}
+		sort(v.begin(), v.end());
+		// rep(i,v.size())
+		// 	cout<<v[i].first<<"  ";
+		cout << kruskal() << endl;
+		v.clear();
+	}
+	return 0;
+}