2013 年 1月 30 日随笔档案 - 电子幼体

最短路算法的整理

摘要： Floyd-Warshall算法 for (int k=1;k<=n;k++) { for (int i=1;i<=n;i++) { for (int j=1;j<=n;j++) { if (a[i][k]+a[k][j]<a[i][j]) { a[i][j]=a[i][k]+a[k][j]; ... 阅读全文

posted @ 2013-01-30 21:53 电子幼体阅读(121) 评论(0) 推荐(0)

POJ 1125 Stockbroker Grapevine

摘要： Stockbroker GrapevineTime Limit:1000MSMemory Limit:10000KTotal Submissions:22127Accepted:12069DescriptionStockbrokers are known to overreact to rumours. You have been contracted to develop a method of spreading disinformation amongst the stockbrokers to give your employer the tactical edge in the st 阅读全文

posted @ 2013-01-30 21:48 电子幼体阅读(127) 评论(0) 推荐(0)

POJ 2253 Frogger

摘要： FroggerTime Limit:1000MSMemory Limit:65536KTotal Submissions:19130Accepted:6222DescriptionFreddy Frog is sitting on a stone in the middle of a lake. Suddenly he notices Fiona Frog who is sitting on another stone. He plans to visit her, but since the water is dirty and full of tourists' sunscreen 阅读全文

posted @ 2013-01-30 16:26 电子幼体阅读(124) 评论(0) 推荐(0)

POJ 3258 Wormholes解题报告

摘要： WormholesTime Limit:2000MSMemory Limit:65536KTotal Submissions:22311Accepted:7958DescriptionWhile exploring his many farms, Farmer John has discovered a number of amazing wormholes. A wormhole is very peculiar because it is a one-way path that delivers you to its destination at a time that is BEFORE 阅读全文

posted @ 2013-01-30 11:55 电子幼体阅读(141) 评论(0) 推荐(0)

Bellman-Ford算法

摘要：贝尔曼-福特算法（Bellman-Ford）是由RichardBellman和Lester Ford创立的，求解单源最短路径问题的一种算法。有时候这种算法也被称为Moore-Bellman-Ford 算法，因为Edward F. Moore也为这个算法的发展做出了贡献。它的原理是对图进行V-1次松弛操作，得到所有可能的最短路径。其优于迪科斯彻算法的方面是边的权值可以为负数、实现简单，缺点是时间复杂度过高，高达O(VE)。但算法可以进行若干种优化，提高了效率。自然语言描述对有向图G(V,E)，用贝尔曼-福特算法求以Vs为源点的最短路径的过程：建立dist[]，表示目前已知源点到各个节点的最短距离阅读全文

posted @ 2013-01-30 11:30 电子幼体阅读(259) 评论(0) 推荐(0)

二分图最大匹配--匈牙利算法

摘要：二分图的基本概念一个无向图G=<V, E>，如果存在两个集合X、Y，使得X∪Y=V， X∩Y=Φ，并且每一条边e={x，y}有x∈X，y∈Y，则称G为一个二分图(bipartite graph)。常用<X, E, Y>来表示一个二分图。若对X中任一x及Y中任一y恰有一边e∈E，使e = {x, y}, 则称G为完全二分图(complete bipartite graph)。当|X| = m，|Y| = n时，完全二分图G记为Km,n。二分图的性质：定理：无向图G为二分图的充分必要条件是，G至少有两个顶点,且其所有回路的长度均为偶数。匹配：设G=<V, E>为阅读全文

posted @ 2013-01-30 10:18 电子幼体阅读(173) 评论(0) 推荐(0)

各大OJ题目分类

摘要： -----------------------------最优化问题-----------------------------------------------------------常规动态规划 SOJ1162 I-Keyboard SOJ2096 Maximum Submatrix SOJ2111 littleken bgSOJ2142 Cow Exhibition SOJ2505 The County FairSOJ2818 QQ音速 SOJ2469 Exploring Pyramids SOJ1833 Base Numbers SOJ2009 Zeros and Ones SOJ20 阅读全文

posted @ 2013-01-30 10:12 电子幼体阅读(393) 评论(0) 推荐(0)

[置顶] ACM训练方案

摘要：初期:一.基本算法:(1)枚举. (poj1753,poj2965)(2)贪心(poj1328,poj2109,poj2586)(3)递归和分治法.(4)递推.(5)构造法.(poj3295)(6)模拟法.(poj1068,poj2632,poj1573,poj2993,poj2996)二.图算法:(1)图的深度优先遍历和广度优先遍历.(2)最短路径算法(dijkstra,bellman-ford,floyd,heap+dijkstra) (poj1860,poj3259,poj1062,poj2253,poj1125,poj2240)(3)最小生成树算法(prim,kruskal) (poj 阅读全文

posted @ 2013-01-30 10:10 电子幼体阅读(186) 评论(0) 推荐(0)

ACM训练方案