CONGRAPH - Connected country
After a strong earthquake many roads of the ancient country GRAPH were destroyed. The country is divided into disconnected areas so that from one area city it is impossible to reach another area city. Pharaoh wants to restore the road infrastructure and connect all the cities. He asks the great Thoth to find the minimum number of roads needed for this.
The first line of input will contain two space separated integer numbers: 0 < N ≤ 800000, number of cities and 0 < M < 4000000, number of roads. Follow M lines. Each line represents cities (numbering is zero based) connected by road. All roads are bidirectional.
One integer number. Answer of the Thoth
Input: 6 6 0 1 0 2 1 2 3 4 3 5 4 5
One road from the city number 1 to the city number 4 makes GRAPH connected.
AC in one go....No need to do the union, just find the no. of disconnected components ans will be one less than that.e.g. in given example, two diconnected components are there so only one road needed.
In the case of DSU, Balance the tree when taking Union else it will result in TLE!
DSU is working fine
My Dsu not working here , got AC with dfs , plz help
#connected components -1