随笔分类 -  图论

摘要：有向图的强连通分量POJ 1236 - Network of Schools(基础)http://acm.pku.edu.cn/JudgeOnline/problem?id=1236题意：问添加多少边可成为完全连通图解法：缩点，看度数/** head-file **/ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /** define-fo... 阅读全文

摘要：Remmarguts' DateTime Limit:4000MSMemory Limit:65536KTotal Submissions:17853Accepted:4879Description"Good man never makes girls wait or breaks an appointment!" said the mandarin duck father. Softly touching his little ducks' head, he told them a story."Prince Remmarguts lives i 阅读全文

摘要：As long as Binbin loves SangsangTime Limit: 2000/1000 MS (Java/Others)Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 2053Accepted Submission(s): 501Problem DescriptionBinbin misses Sangsang so much. He wants to meet with Sangsang as soon as possible.Now Binbin downloads a map from ELG 阅读全文

摘要：Park VisitTime Limit: 6000/3000 MS (Java/Others)Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 85Accepted Submission(s): 34Problem DescriptionClaire and her little friend, ykwd, are travelling in Shevchenko's Park! The park is beautiful - but large, indeed. N feature spots in the 阅读全文

摘要：E. Ciel the Commandertime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard output现在Fox Ciel成为了Tree Land的指挥官。Tree Land，正如它的名字所说，有n个城市由n-1条无向道路连接，并且其中任意两个城市之间总是存在一条路径。Fox Ciel需要在每个城市分配一个官员。每个官员都有一个等级---一个’A’到’Z’之间的字母。所以会有26个不同的等级，’A’是最高的，’Z’是最低的。每个等级都有足够的官员。但是必 阅读全文

摘要：1. 树的直径概念：树中的最长路。求法：两次深搜或DP。1-两次深搜：任找一点A为源点，深搜遍历得到最远点B，这个最远点B必定在直径中（感性想想，以A点为源点找到的最长路后面一段必定属于树的直径的一部分）；再以这个最远点B为源点深搜遍历求一个最长路，这个最长路即为树的直径。2-DP：显然最长路的两个端点必然是叶子或者根节点。设f(i)表示到i最远的叶子，g(i)表示到i次远的叶子，则有f(i)=max{f(j)}+1;g(i)=second{f(j)}+1;其中j必须是i的儿子，计算顺序是自底向上。最终答案为max{f(i)+g(i)}+12. 树的中心概念：树的直径的中点。求法：有多种，如D 阅读全文

摘要：Triangle LOVETime Limit: 2000/1000 MS (Java/Others)Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 1629Accepted Submission(s): 693Problem DescriptionRecently, scientists find that there is love between any of two people. For example, between A and B, if A don’t love B, then B must love 阅读全文

摘要：Power transmissionTime Limit: 10000/5000 MS (Java/Others)Memory Limit: 131072/131072 K (Java/Others)Total Submission(s): 1403Accepted Submission(s): 533Problem DescriptionThe project West-East power transmission is famous around the world. It transmits the electricity from western areas to east Chin 阅读全文

摘要：Seikimatsu Occult TonneruTime Limit: 12000/6000 MS (Java/Others)Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1341Accepted Submission(s): 313Problem DescriptionDuring the world war, to avoid the upcoming Carpet-bombing from The Third Reich, people in Heaven Empire went to Great Tunne 阅读全文

摘要：MatrixTime Limit: 4000/2000 MS (Java/Others)Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 825Accepted Submission(s): 212Problem DescriptionLet A be a 1*N matrix, and each element of A is either 0 or 1. You are to find such A that maximize D=(A*B-C)*AT, where B is a given N*N matrix w 阅读全文

摘要：#include #include #include #include #include #include #include #include #include #include using namespace std; const int maxn=1111; const int maxm=1111111; const int INF=1e9; struct Edge{ int from,to,cap,flow; }; struct Dinic{ int n,m,s,t; vectoredges; vectorG[maxn]; ... 阅读全文

摘要：#include #include #include #include #include #include #include #include #include #include using namespace std; const int maxn=11111; struct Edge{ int from,to; int dist; }; struct BellmanFord{ int n,m; vector edges; vector G[maxn]; bool inq[maxn]; int d[maxn]... 阅读全文

摘要：IIUPC2006Problem G: Going in Cycle!!Input: standard inputOutput: standard outputYou are given a weighted directed graph withnvertices andmedges. Each cycle in the graph has a weight, which equals to sum of its edges. There are so many cycles in the graph with different weights. In this problem we wa 阅读全文

摘要：Problem C: A Walk Through the ForestJimmy experiences a lot of stress at work these days, especially since his accident made working difficult. To relax after a hard day, he likes to walk home. To make things even nicer, his office is on one side of a forest, and his house is on the other. A nice wa 阅读全文

摘要：Problem D: Airport ExpressIn a small city called Iokh, a train service,Airport-Express, takes residents to the airport more quickly than other transports. There are two types of trains in Airport-Express, theEconomy-Xpressand theCommercial-Xpress. They travel at different speeds, take different rout 阅读全文

摘要：模板#include #include #include #include #include #include using namespace std; const int maxn=11111; const int maxm=11111; const int INF=1e9; struct Edge{ int from,to,dist; }; struct HeapNode{ int d,u; bool operatorrhs.d; } }; struct Dijkstra{ int n,m; vector edges; ... 阅读全文

摘要：The Bandulu Space Agency (BSA) has plans for the following three space missions:Mission A: Landing on Ganymede, the largest moon of Jupiter.Mission B: Landing on Callisto, the second largest moon of Jupiter.Mission C: Landing on Titan, the largest moon of Saturn.Your task is to assign a crew for eac 阅读全文

摘要：struct TWO_SAT{ int n; vectorG[maxn*2]; bool mark[maxn*2]; int S[maxn*2],c; bool dfs(int x){ if (mark[x^1]) return false; if (mark[x]) return true; mark[x]=true; S[c++]=x; for (int i=0;in=n; for (int i=0;i0) mark[S[--c]]=false; ... 阅读全文

摘要：Problem B: The Largest CliqueGiven a directed graphG, consider the following transformation. First, create a new graphT(G)to have the same vertex set asG. Create a directed edge between two verticesuandvinT(G)if and only if there is a path betweenuandvinGthat follows the directed edges only in the f 阅读全文

摘要：二分图（AC）/*=================================*\ | 节点u所在的强连通分量是否为二分图 | Call: bipartite(u); \*=================================*/ int color[maxn]; bool bipartite(int u) { for (int i=head[u];i!=-1;i=edges[i].next) { int v=edges[i].to; if (color[v]&&color[v]==color[u]) return fals... 阅读全文