Euler's Formula

Author: Benjamin Qi

A formula for finding the number of faces in a planar graph.

Introduction

Any help would be appreciated! Just submit a Pull Request on Github.

Status	Source	Problem Name	Difficulty	Tags
	APIO	2017 - Land of the Rainbow Gold	Very Hard	Show Tags 2DRQ, Euler's Formula, Persistent Segtree

Any help would be appreciated! Just submit a Pull Request on Github.

Status	Source	Problem Name	Difficulty	Tags
	Plat	Valleys	Very Hard

Any help would be appreciated! Just submit a Pull Request on Github.

int N, h[750][750];
ll ans;
vector<pair<int,pi>> v;

int hsh(int a, int b) {
	return N*a+b;
}

const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1};

Source	Problem Name	Difficulty	Tags
Kattis	Island Archipelago	Very Hard	Show Tags DSU, Euler's Formula
CF	Kevin & Grid	Very Hard	Show Tags Euler's Formula, FFT
CF	Rectangles & Connected Regions	Very Hard	Show Tags Euler's Formula
Plat	Paint by Letters	Very Hard	Show Tags Euler's Formula