ypxrain的博客

DescriptionByteasar intends to throw up a party. Naturally, he would like it to be a success. Furthermore, Byteasar is quite certain that to make it so it suffices if all invited guests know each other

题意给出n,m,x,y，要求构造一个n*m的矩形使得其元素和大于0且任意一个x*y的子矩形的元素和小于0。 x,y,n,m<=500分析很容易想到在所有横坐标为x的倍数，纵坐标为y的倍数的格子填上-x*y，其余格子全填1，这样就可以保证每个子矩阵的和小于0。但是这样在多出来的格子比较少的时候可能会导致整个矩形的元素和小于0。于是我们可以设一个较大的常数d，把每个格子填上d...