def lowerBound(a, x):
    l = 0
    r = len(a)
    while l < r:
        mid = (l + r) // 2
        if a[mid] >= x:
            r = mid
        else:
            l = mid + 1
    return l

if __name__ == "__main__":
    a1 = [1, 3, 5, 7, 9]
    x1 = 5
    print(f"数组{a1}中第一个≥{x1}的位置：{lowerBound(a1, x1)}")

    x2 = 6
    print(f"数组{a1}中第一个≥{x2}的位置：{lowerBound(a1, x2)}")

    x3 = 10
    print(f"数组{a1}中第一个≥{x3}的位置：{lowerBound(a1, x3)}")

    x4 = 0
    print(f"数组{a1}中第一个≥{x4}的位置：{lowerBound(a1, x4)}")