Merge pull request deutranium#248 from keshav2712/master

Added Kruskals Algorithm in C

Author: codelixir

classicalAlgos/kruskalsAlgorithm/kruskals.c

@@ -0,0 +1,75 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#define N 1000005
+#define I 10000000005
+
+typedef long long int ll;
+typedef struct Node
+{
+    ll cost;
+    ll vertex1;
+    ll vertex2;
+} Node;
+int comparator(const void *a, const void *b)
+{
+    return ((*(Node *)a).cost - (*(Node *)b).cost);
+}
+ll parent(ll set[], ll i)
+{
+    if (set[i] == i)
+        return i;
+    else
+    {
+        set[i] = parent(set, set[i]);
+        return set[i];
+    }
+}
+void setUnion(ll set[], ll a, ll b)
+{
+    a = parent(set, a);
+    b = parent(set, b);
+    if (a != b)
+        set[b] = a;
+}
+void initSet(ll set[], ll v)
+{
+    for (ll i = 0; i < v; i++)
+        set[i] = i;
+}
+long long int kruskals(Node m[], ll e, ll n)
+{
+    long long int sum = 0;
+    ll set[N];
+    initSet(set, n);
+    ll j = 0;
+    ll counter = 0;
+    qsort(m, e, sizeof(Node), comparator);
+    while ((j < n - 1) && (counter < e))
+    {
+        ll x = m[counter].vertex1, y = m[counter].vertex2;
+
+        if ((parent(set, x) != parent(set, y)) && (counter < e))
+        {
+            sum += m[counter].cost;
+            setUnion(set, x, y);
+            j++;
+        }
+        counter++;
+    }
+    return sum;
+}
+int main()
+{
+    ll n = 0, X = 0;
+    scanf("%lld %lld", &n, &X);
+    Node edges[N];
+    assert(edges);
+    for (ll i = 0; i < X; i++)
+    {
+        scanf("%lld %lld %lld", &edges[i].vertex1, &edges[i].vertex2, &edges[i].cost);
+    }
+    printf("%lld\n", kruskals(edges, X, n));
+    return 0;
+}