Question

I’m writing a solution for a simple programming problem, but I can’t get map::find() to work. I am using maps to mark visited vertices when using BFS. I know I could use some other data structure, such as a 2D bool array, but I’m just really eager to make it work with maps.
Here’s my code: http://pastebin.com/mANej4vp

The problem is that visited[tempR] is always true, even though the tempR position hasn’t been visited yet. And the visited.size() is 1, but it responds to both the visited[now] and visited[tempR] as true; while tempR is not equal to now.

Duom.in file should contain this: http://pastebin.com/L7qMG0bd

Do you have any idea why is this happening?

Answer 1

Your operator< and operator== are inconsistent

for two positions

pos p1 = {1, 2, 3, 4};
pos p2 = {1, 10, 20, 30};

bool b1 = !(p1 < p2) && !(p2 < p1);
bool b2 = p1 == p2;

b1 is true, so b2 must be true by definition, but it’s not.

In other words, rewrite your operator< to do proper comparison, not just Hx