\(>Codeforces \space 550 D. Regular Bridge<\) 题目大意 :给出 \(k\) ,让你构造出一张点和边都不超过 \(10^6\) 的无向图,使得每个点的度数都为 \(k\) 且至少有一条桥边. \(1≤ k ≤ 100\) 解题思路 : 通过观察可以发现当 \(k\) 为偶数的时候必然无解 证明:先假设当 \(k\) 是偶数的时候可以构造出来. 那么对于这张图的每一条桥边,必然连接这两个联通块,那么单独考虑这两个联通块,有且仅有一个端点的度数是 \(k…

Codeforce 550 D. Regular Bridge 解析(思維.圖論) 今天我們來看看CF550D 題目連結 題目 給你一個\(k\le100\),請構造出一個至少有一個Bridge的,每個點的degree都是\(k\)的無向圖. 前言 學到了Handshaking Lemma @copyright petjelinux 版權所有 觀看更多正版原始文章請至petjelinux的blog 想法 首先既然要有一個Bridge,我們就從已經有一個Bridge的圖開始構造. 可能會發現到\(…

D. Regular Bridge Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/D Description An undirected graph is called k-regular, if the degrees of all its vertices are equal k. An edge of a connected graph is called a b…

 Regular Bridge time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output An undirected graph is called k-regular, if the degrees of all its vertices are equal k. An edge of a connected graph is cal…

D. Regular Bridge time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output An undirected graph is called k-regular, if the degrees of all its vertices are equal k. An edge of a connected graph is c…

Problem  Codeforces #550 (Div3) - G.Two Merged Sequences Time Limit: 2000 mSec Problem Description Two integer sequences existed initially, one of them was strictly increasing, and another one — strictly decreasing. Strictly increasing sequence is a…

Regular Bridge An undirected graph is called k-regular, if the degrees of all its vertices are equal k. An edge of a connected graph is called a bridge, if after removing it the graph is being split into two connected components. Build a connected un…

题意与分析 图论基础+思维题. 代码 #include <bits/stdc++.h> #define MP make_pair #define PB emplace_back #define fi first #define se second #define ZERO(x) memset((x), 0, sizeof(x)) #define ALL(x) (x).begin(),(x).end() #define rep(i, a, b) for (repType i = (a); i &…

题目大意:给定k(1≤k≤100),要求构造一张简单无向连通图,使得存在一个桥,且每一个点的度数都为k k为偶数时无解 证明: 将这个图缩边双,能够得到一棵树 那么一定存在一个叶节点,仅仅连接一条桥边 那么这个边双内部全部点度数之和为偶数 除掉连出去的桥边外度数之和为奇数 故不合法 然后k为奇数的时候我们仅仅须要构造两个对称的边双被一条桥边连接的图即可了 因为每一个点度数为k.因此每一边至少须要k+1个点 可是k+1个点奇偶性不合法.因此每一边至少须要k+2个点 如今问题转化成了给定一个度数数组…

题目链接:http://codeforces.com/problemset/problem/5/C 题目大意:给出一串字符串只有'('和')',求出符合括号匹配规则的最大字串长度及该长度的字串出现的次数.解题思路:设dp[i]为到i的最大括号匹配,我们每次遇到一个'('就将其下标存入栈中,每次遇到')'就取出当前栈中里它最近的'('下标即栈顶t.不能直接dp[i]=i-t+1,比如(()()())这样的例子就会出错,应为dp[i]=dp[i-1]+i-t+1. 代码 #include<bits/…