Spring:
Xiaoming: 3
Xiao Qiang: 2.
Xiaojun: 1
Xiaohua: 0
Autumn: suppose Xiao Ming made an X cm.
The order may be:
Xiaoming Xiaohua Xiaojun Xiao Qiang
Xxx+2xx-2 is invalid!
Xiaoming Xiaohua Xiao Qiang Xiaojun
X x+2 x- 1 x- 1 is invalid!
Xiaojun Xiao Qiang Xiaoming Xiaohua
X+4 x+2 x X+2 does not hold!
Xiao Qiang Xiaojun Xiaoming Xiaohua
X+3x+3x+2 does not hold!
Xiao Qiang Xiaoming Xiaohua Xiaojun
X+2 x x+2 x does not hold!
Xiaojun Xiaoming Xiaohua Xiao Qiang
X+3 x x+2 x- 1 hold!
So Xiaojun is the tallest.