Merge pull request matthewsamuel95#950 from JayRajM97/master

Create DijkstrasSTPUsingVectors.cpp

Author: matthewsamuel95

Graph/DijkstrasSPT/DijkstrasUsingVectors.cpp

@@ -0,0 +1,60 @@
+#include <iostream>
+#include <stdio.h>
+#include <cstdlib>
+#include <queue>
+#include <vector>
+#include <algorithm>
+using namespace std;
+ typedef pair<int, int> ii;
+typedef vector<int> vi;
+typedef vector<ii> vii;
+ using namespace std;
+ int n, m, S, T, w;
+ vector<vii> AdjList;
+vi dist;
+priority_queue<ii, vector<ii>, greater<ii>> pq;
+ void dijkstra(int s)
+{
+     dist.assign(n, 1e9);
+    dist[s] = 0;
+     pq.push(ii(0, s));
+     while (!pq.empty())
+    {
+        ii front = pq.top(); pq.pop();
+        int d = front.first, u = front.second;
+        if (d > dist[u])
+            continue;
+        for (int j = 0; j < (int)AdjList[u].size(); j++)
+        {
+            ii v = AdjList[u][j];
+            if (dist[u] + v.second < dist[v.first])
+            {
+                dist[v.first] = dist[u] + v.second;
+                pq.push(ii(dist[v.first], v.first));
+            }
+        }
+    }
+     if (dist[T] == 1e9)
+        cout << "unreachable" << endl;
+    else
+        cout << dist[T] << endl;
+}
+ int main()
+{
+    int numCases;
+    cin >> numCases;
+    while (numCases--)
+    {
+        scanf("%d %d %d %d", &n, &m, &S, &T);
+         AdjList.assign(n, vii());
+         int n1, n2;
+        for (int i = 0; i < m; i++)
+        {
+            scanf("%d %d %d", &n1, &n2, &w);
+            AdjList[n1].push_back(ii(n2, w));
+            AdjList[n2].push_back(ii(n1, w));
+        }
+        dijkstra(S);
+    }
+     return 0;
+}