2021.11.03 P2886 [USACO07NOV]Cow Relays G(矩阵+floyed) [P2886 USACO07NOV]Cow Relays G - 洛谷 | 计算机科学教育新生态 (luogu.com.cn) 题意: 给出一张无向连通图,求S到E经过k条边的最短路. 分析: 对于floyed,在第k个点时,任意的i到j之间的最短路已经经过了(k-1)个点.当fa[i] [j]经过了x条边,fb[i] [j]经过了y条边,想要算出经过了x+y条边,只需要按照floyed的算…

题目 For their physical fitness program, \(N (2 ≤ N ≤ 1,000,000)\) cows have decided to run a relay race using the \(T (2 ≤ T ≤ 100)\) cow trails throughout the pasture. Each trail connects two different intersections \((1 ≤ I1_i ≤ 1,000; 1 ≤ I2_i ≤ 1,…

题目大意 洛谷链接 给定一张\(T\)条边的无向连通图,求从\(S\)到\(E\)经过\(N\)条边的最短路长度. 输入格式 第一行四个正整数\(N,T,S,E\),意义如题面所示. 接下来\(T\)行每行三个正整数\(w,u,v\)分别表示路径的长度,起点和终点. 输出格式 一行一个整数表示图中从\(S\)到\(E\)经过\(N\)条边的最短路长度. 数据范围 对于所有的数据,保证\(1\le N\le 10^6,2\le T\le 100\). 所有的边保证\(1\le u,v\le 100…

题目大意 给出一张无向连通图(点数小于1000),求S到E经过k条边的最短路. 算法 这是之前国庆模拟赛的题 因为懒 所以就只挑一些题写博客 在考场上写了个dp 然后水到了50分 出考场和神仙们一问才知道是lyd蓝书原题 我们考虑有两个floyd的矩阵 A代表走了x条边的矩阵 B代表走了y条边的矩阵 那么我们想求出C这个代表走了(x + y)这个矩阵的值呢 我们考虑这么一个式子 \(C[i][j] = min( A[i][k] + B[k][j] )\) 然后我们发现 其中\(A[i][k] +…

本题就是求两点间只经过n条边的最短路径,定义广义的矩阵乘法,就是把普通的矩阵乘法从求和改成了取最小值,把内部相乘改成了相加. 代码包含三个内容:广义矩阵乘法,矩阵快速幂,离散化: 1 #include<bits/stdc++.h> 2 using namespace std; 3 const int INF=0x3f3f3f3f; 4 const int N=120; 5 int Hash[1000005],cnt=0;//用于离散化 6 struct matrix{ 7 int m[N][N…

map+floyed+矩阵乘法(倍增floyed) # include <stdio.h> # include <stdlib.h> # include <iostream> # include <algorithm> # include <string.h> # include <map> # define IL inline # define RG register # define Fill(a, b) memset(a, b,…

Cow Relays Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 7335   Accepted: 2878 Description For their physical fitness program, N (2 ≤ N ≤ 1,000,000) cows have decided to run a relay race using the T (2 ≤ T ≤ 100) cow trails throughout…

Cow Relays Time Limit: 1000MS   Memory Limit: 65536K Total Submissions:9207   Accepted: 3604 Description For their physical fitness program, N (2 ≤ N ≤ 1,000,000) cows have decided to run a relay race using the T (2 ≤ T ≤ 100) cow trails throughout t…

Cow Relays Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 5411   Accepted: 2153 Description For their physical fitness program, N (2 ≤ N ≤ 1,000,000) cows have decided to run a relay race using the T (2 ≤ T ≤ 100) cow trails throughout…

Cow Relays Time Limit: 1000/1000 MS (Java/Others)     Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 80     Accepted Submission(s): 13 Description Farmer John has formed a relay team for a race by choosing K (2 ≤ K ≤ 40) of his cows.…