题目链接: World Exhibition Time Limit: 2000/1000 MS (Java/Others)     Memory Limit: 32768/32768 K (Java/Others) Problem Description   Nowadays, many people want to go to Shanghai to visit the World Exhibition. So there are always a lot of people who are…

这题建图没什么特别 x个条件:Sb-Sa<=c y个条件:Sa-Sb<=-c 题目问的是.1和n之间的关系. 有负环的话,整个就不可能成立,输出-1 假设图是连通的(1到n是连通的),就输出d[n] 不连通就是题目中说-2的情况. 原来我们建图一般加入一个附加结点,或者開始就把全部点入队,就是考虑到不连通的问题,所以加入一个没有意义的条件. #include <iostream> #include <cstring> #include <string> #i…

World Exhibition Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1754    Accepted Submission(s): 886 Problem Description Nowadays, many people want to go to Shanghai to visit the World Exhibitio…

Layout Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 9687   Accepted: 4647 Description Like everyone else, cows like to stand close to their friends when queuing for feed. FJ has N (2 <= N <= 1,000) cows numbered 1..N standing along a…

转自:http://blog.csdn.net/shahdza/article/details/7779273 最短路 [HDU] 1548 A strange lift基础最短路(或bfs)★2544 最短路 基础最短路★3790 最短路径问题基础最短路★2066 一个人的旅行基础最短路(多源多汇,可以建立超级源点和终点)★2112 HDU Today基础最短路★1874 畅通工程续基础最短路★1217 Arbitrage 货币交换 Floyd (或者 Bellman-Ford 判环)★124…

Intervals Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 5488    Accepted Submission(s): 1999 Problem Description You are given n closed, integer intervals [ai, bi] and n integers c1, ..., cn.…

出处:http://blog.csdn.net/shahdza/article/details/7779273 最短路 [HDU] 1548    A strange lift基础最短路(或bfs)★ 2544    最短路  基础最短路★ 3790    最短路径问题基础最短路★ 2066    一个人的旅行基础最短路(多源多汇,可以建立超级源点和终点)★ 2112    HDU Today基础最短路★ 1874    畅通工程续基础最短路★ 1217    Arbitrage   货币交换…

Time Limit: 1500MS Memory Limit: 131072K Description During the kindergarten days, flymouse was the monitor of his class. Occasionally the head-teacher brought the kids of flymouse's class a large bag of candies and had flymouse distribute them. All…

//Accepted 2692 KB 1282 ms //差分约束 -->最短路 //TLE到死,加了输入挂,手写queue #include <cstdio> #include <cstring> #include <iostream> #include <queue> #include <cmath> #include <algorithm> using namespace std; /** * This is a docu…

偶尔做了一下差分约束. 题目大意:给出n个军营,每个军营最多有ci个士兵,且[ai,bi]之间至少有ki个士兵,问最少有多少士兵. --------------------------------------------------- 差分约束:就是利用多个不等式来推导另一个不等式. 由于不等式a-b<=c和求最短路径时的三角形不等式相同,就变成了求最短路. 所有不等式化为a-b<=c的形式,则建造b到a的边,权为c. 求a到b的最短距离,则转化为b-a<=c,距离的值为c. 该题中:…