CodeForces - 1016D Vasya And The Matrix

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CodeForces - 1016D Vasya And The Matrix

题面在这里! 很明显二进制每一位都是无关的,所以可以先把原问题简化:给矩阵中的每个位置填入0/1,使得特定行/列有奇数个1,其他行/列有偶数个1. 一个比较好想的方法是对行和列列出 n+m 个异或方程,其中有 n*m 个变量,随便求出一组解就好了(如果有的话). 但这个貌似并不是很好写... 可以把解异或方程转化成在一个完全二分图(左n个点,右m个点)上选边,每个点可以是黑的(对应行/列要求有奇数个1)或者白的(反之),每选一条边就要把两端的点的黑白性颠倒. 然后发现这是一个经典问题,显然选…

Educational Codeforces Round 48 (Rated for Div. 2) D 1016D Vasya And The Matrix (构造)

D. Vasya And The Matrix time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Now Vasya is taking an exam in mathematics. In order to get a good mark, Vasya needs to guess the matrix that the te…

1016D.Vasya And The Matrix#矩阵存在

题目出处:http://codeforces.com/contest/1016/problem/D #include<iostream> #define ll long long int #define inf 0x3f3f3f3f #define N 1005 using namespace std; ll a[N],b[N]; ll xn[N][N]; ll n,m; int main(){ /**/ cin>>n>>m; ll x = ; ;i<n;i++)…

Vasya And The Matrix CodeForces - 1016D （思维+构造）

Now Vasya is taking an exam in mathematics. In order to get a good mark, Vasya needs to guess the matrix that the teacher has constructed! Vasya knows that the matrix consists of n rows and m columns. For each row, he knows the xor (bitwise excluding…

D. Vasya And The Matrix(Educational Codeforces Round 48)

D. Vasya And The Matrix time limit per test2 seconds memory limit per test256 megabytes inputstandard input outputstandard output Now Vasya is taking an exam in mathematics. In order to get a good mark, Vasya needs to guess the matrix that the teache…

CF 1042 E. Vasya and Magic Matrix

E. Vasya and Magic Matrix http://codeforces.com/contest/1042/problem/E 题意: 一个n*m的矩阵,每个位置有一个元素,给定一个起点,每次随机往一个小于这个点位置走,走过去的值为欧几里得距离的平方,求期望的值. 分析: 逆推期望. 将所有值取出,按元素大小排序,然后最小的就是0,往所有大于它的转移即可,复杂度n^2,见下方考试代码. 考虑每个点,从所有小于它的元素转移.排序后,维护前缀和,可以做到O(1)转移. $f[i] =…