在m×n的矩阵中有一个元素a[i,j]满足下述条件：a[i,j]既是第i行元素中的最小值，又是第j列元素中的最大值（称为鞍点），此程序是求矩阵鞍点的算法-In the m × n matrix has an element of a [i, j] satisfy the following conditions: a [i, j] is not only the first i elements of the minimum trip, but also is the first j eleme