'''
Author: SJ2050
Date: 2021-10-16 22:04:07
LastEditTime: 2021-10-16 23:25:30
Version: v0.0.1
Description: Solution for homework7.
Copyright © 2021 SJ2050
'''
def searchMatrix(matrix, target):
    if (len(matrix) == 0 ):
        return False

    i = len(matrix)-1
    j = 0
    while (i>=0 and j < len(matrix[0])):
        if (matrix[i][j] == target):
            return True
        elif (matrix[i][j] < target):
            j += 1
        elif(matrix[i][j] > target):
            i -= 1

    return False

if __name__ == "__main__":
    matrix = [
            [1, 4, 7, 11, 15],
            [2, 5, 8, 12, 19],
            [3, 6, 9, 16, 22],
            [10, 13, 14, 17, 24],
            [18, 21, 23, 26, 30]
            ]
    target = 20
    print(searchMatrix(matrix, target))

    # 算法说明：
    # 从矩阵左下角，先排除不符合条件的列，再排除不符合条件的行，将范围一直往右上角缩小