zoj3732&& hdu4797 Graph Reconstruction

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zoj3732&& hdu4797 Graph Reconstruction

Graph Reconstruction Time Limit: 2 Seconds Memory Limit: 65536 KB Special Judge Let there be a simple graph with N vertices but we just know the degree of each vertex. Is it possible to reconstruct the graph only by these information? A sim…

2013长沙 G Graph Reconstruction (Havel-Hakimi定理)

Graph Reconstruction Time Limit: 2 Seconds Memory Limit: 65536 KB Special Judge Let there be a simple graph with N vertices but we just know the degree of each vertex. Is it possible to reconstruct the graph only by these information? A sim…

Codeforces Round #192 (Div. 1) C. Graph Reconstruction 随机化

C. Graph Reconstruction Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/329/problem/C Description I have an undirected graph consisting of n nodes, numbered 1 through n. Each node has at most two incident edges. For each pa…

2013亚洲区域赛长沙站 ZOJ 3732 Graph Reconstruction

题目链接 Graph Reconstruction 题意给你无向图每个点的度数, 问是否存在唯一解, 存在输出唯一解, 多解输出两个, 无解输出IMPOSSIBLE 思路这里用到了 Havel-Hakimi定理, 实际上就是按照度数构图的一种贪心策略. 这样能判断出来一个解或无解, 多解的情况, 只要在比较构图时最后面两个点的当前度数一样, 那么选其一都是可行的, 但是选其一的情况有保证了另外一个肯定没有连上, 所以能找到其它解. 代码 #include <bits/stdc++.h> #…

ZOJ3732 Graph Reconstruction Havel-Hakimi定理

分析: 给定一个非负整数序列{dn},若存在一个无向图使得图中各点的度与此序列一一对应,则称此序列可图化. 进一步,若图为简单图,则称此序列可简单图化 (来自百度百科) 可简单图化的判定可以用Havel-Hakimi定理,然后简述 Havel-Hakimi定理 Havel-Hakimi定理的过程: 1,按度数排序. 2,选取度数最大的点,如果该点度数为0,结束,有解 3,每次选一个度数最大的点,然后将后面的点的度数依次减1,表示该顶点和相应的顶点有边相连, 如果有点的度数减到负数,结束,无解.…

CodeForces-329C（div1）：Graph Reconstruction（随机&构造）

I have an undirected graph consisting of n nodes, numbered 1 through n. Each node has at most two incident edges. For each pair of nodes, there is at most an edge connecting them. No edge connects a node to itself. I would like to create a new graph…

CF 329C(Graph Reconstruction-随机化求解-random_shuffle(a+1,a+1+n))

C. Graph Reconstruction time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output I have an undirected graph consisting of n nodes, numbered 1 through n. Each node has at most two incident edges. Fo…