1.矩阵链乘 Matrix Chain Multiplication01-14 收起 题目链接: https://www.luogu.com.cn/problem/UVA442题意:给定若干个矩阵表达式,以及涉及到的矩阵的行与列 定义矩阵相乘次数为矩阵1的行数矩阵1的列数(矩阵2的行数)矩阵2的列数 计算每个表达式的矩阵相乘次数(若不满足矩阵乘法规律输出error)思路...
UVA442 矩阵链乘 Matrix Chain Multiplication 题意: 这道题也是在不改变原序列每个元素位置的前提下,看每个元素与他身边的两个元素那个先结合能得到最大的能量 题解: 很明显这是一道区间dp的题目,这道题要断环成链,这道题需要考虑在这个区间上某个元素先与那个元素结合更好,而如果我们采用了区间dp的模板,那么...
Matrix t1 = dq.back(); dq.pop_back(); if(t1.y != t2.x) { flag = false; break; } ans += t1.x * t1.y * t2.y; dq.push_back(Matrix(t1.x, t2.y)); } else { dq.push_back(Map[str[i]]); } } while(!dq.empty()) { Matrix t1 = dq.front(); dq.pop_front();...
一、问题设A1,A2,…,An为n个矩阵的序列,其中Ai为Pi-1*P为阶矩阵,这个矩阵链的输入用向 量P=<P0,P1,…Pn> 给出。二、解析 r表示问题规模长度,r=1表示矩阵自身相乘,由于是自身相乘,表示为0,r=2表示两个两个矩阵相乘,如m[1][2]表示A1A2,为1020*5数组m表示矩阵相乘,s[i][j]=k,表示在k后加括号...
UVA - 442 Matrix Chain Multiplication 题目大意:给出一系列矩阵,然后再给一系列表达式,求一个有几个元素相乘 解题思路:用栈来存储,遇到右括号就弹出两个,然后把结果相加,再压入变换后的矩阵 #include<cstdio> #include<cstring> #include<stack> using namespace std;...
简介:UVA442 矩阵链乘 Matrix Chain Multiplication 题目描述 思路:首先要明白以下几点: 什么是矩阵乘法?(大概学过线代的都知道) 什么矩阵不可乘? A a*b B c*d 当 b = c时,两个矩阵可以相乘,同时结果为 C a*d 矩阵乘法的次数如何计算: 可以相乘的情况下 次数 = a*b*d (a*c*d也行) 这可以自己推...
Matrix multiplication problem is a typical example of dynamical programming. Suppose you have to evaluate an expression like A*B*C*D*E where A,B,C,D and E are matrices. Since matrix multiplication is associative, the order in which multiplications are performed is arbitrary. However, the numbe...
Since matrix multiplication is associative, the order in which multiplications are performed is arbitrary. Howev...Matrix Chain Multiplication Problem Description Matrix multiplication problem is a typical example of dynamical programming. Suppose you have to evaluate an expression like A*B*C*D*E ...
Journal of Applied Computer Science & MathematicsB. Bhowmik, "Simplified optimal parenthesization scheme for matrix chain multiplication problem using bottom-up practice in 2- tree structure," Journal of Applied Computer Science & Mathematics, vol. 11, no. 5, pp. 9-14, 2011....
#include<bits/stdc++.h> using namespace std; int main(){ int n,a,b; scanf("%d%*c",&n);//%*c用来吸收换行符 map<char,pair<int,int>>matrix;//存储矩阵及其行列维度 for(int i=0;i<n;++i){ char c; scanf("%c%d%d%*c",&c,&a,&b); matrix[c]={a,b}; } string line; wh...