描述





元素以对角线为对称轴对应相等的矩阵。







采用特殊矩阵的压缩存储方式。即使用一维数组保存下三角的矩阵元。





输入





第一行输入矩阵的阶n；



第二行按行序排列的所有下三角矩阵元。（中间用空格分隔）



（例如上图所示矩阵的输入次序为：1 5 0 1 8 9 3 0 2 5 7 0 6 1 3）



第三行为正整数 i和j（0< i, j <=n）-Describe the elements to a diagonal matrix equal to the corresponding axis of symmetry. Compressed using a special matrix storage. That the use of one-dimensional array containing the lower triangular matrix elements. Enter the first line of the input matrix of order n　the second row by row sequence alignment of all the lower triangular matrix elements. (Separated by a space) (for example, the input matrix shown above order: 150,189,302,570,613) The third act positive integers i and j (0 < i, j <　= n)