【CF27D】Ring Road 2（二分图、紫题）

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最新推荐文章于 2025-12-31 21:25:26 发布 · 1.2k 阅读

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#算法 #c++ #深度优先

Ring Road 2 - 洛谷

第一道独立AC的紫题。（十分激动）

# Ring Road 2

## 题面翻译

有n个城市，1->2->3->...->n->1，形成一个环，现在要添加m条给定的路，路可以建设在环内或环外，求如何建设可以使得新的路两两不相交（端点除外）。

## 题目描述

It is well known that Berland has $ n $ cities, which form the Silver ring — cities $ i $ and $ i+1 $ ( $ 1<=i<n $ ) are connected by a road, as well as the cities $ n $ and $ 1 $ . The goverment have decided to build $ m $ new roads. The list of the roads to build was prepared. Each road will connect two cities. Each road should be a curve which lies inside or outside the ring. New roads will have no common points with the ring (except the endpoints of the road).