该问题可描述为：对于给定的正整数n，按照2个同号下面都是+号，2个异号下面都是-号的规则生成符号三角形，计算有多少个不同的符号三角形，使其所含的+和-的个数相同。本程序使用回溯法解决符号三角形问题。-The problem can be described as: for a given positive integer n, in accordance with the with the No. 2 the following is+ number, two different numbers below are- number of rules generated triangle symbol, calculation of the number of different symbols triangle, so that the content of+ and- the number of the same. This program uses backtracking method to solve the problem of symbol triangle.