https://mirror.codeforces.com/contest/2171/submission/365464004

My idea is simple. Divide the array into maximal strictly increasing subarrays.

Inside each subarray, connect adjacent elements with undirected edges.

For every subarray i starting from the second one, connect the last element of that subarray to the minimum element that appeared before it (I maintain a running minimum from previous parts).

After building the graph, I run DFS to check if the graph becomes connected.

If it is connected, I print "yes" and output the tree.

My code builds the graph exactly like this, but it gives wrong answers on some test.

So I want to know:

Is the logic itself incorrect, or is there likely an implementation mistake?

If the logic is wrong, where exactly does this idea fail?

Any hints would help.