{"trustable":false,"sections":[{"title":"Describe","value":{"format":"HTML","content":"给出一个N*N的矩阵,并且给出他们的初始值,并且给出这样的两种类型的操作:\u003cbr\u003e\n1.修改某个点的权值;\u003cbr\u003e\n2.查询某个子矩阵的最大权值。"}},{"title":"Input","value":{"format":"HTML","content":"一个整数N(0 ≤ N ≤ 505);\u003cbr\u003e\nN*N的矩阵,Matrix[i][j](-1000000000 ≤ Matrix[i][j] ≤ 1000000000)。\u003cbr\u003e\n一个整数Q(0 ≤ Q ≤ 40007),代表Q次操作;\u003cbr\u003e\nQ次操作:\u003cbr\u003e\nq xl yl xr yr:表示查询(xl, yl)为左下角,(xr, yr)为右上角的子矩阵的最大权值;\u003cbr\u003e\nc xi yi w:表示修改(xi, yi)点的权值为w(-1000000000 ≤ w ≤ 1000000000)。"}},{"title":"Output","value":{"format":"HTML","content":"对于每次询问,一行输出答案。"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e\n1\n1\n3\nq 1 1 1 1\nc 1 1 0\nq 1 1 1 1\n\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e\n1\n0\n\u003c/pre\u003e"}}]}