b.py

#!/usr/bin/env python3
import collections


def get_isosceles_trapezoid_num(edges):
    d={}
    sorted(edges)
    for edge in edges:
        d[edge] = d.get(edge,0) + 1
    #字典排序
    d = collections.OrderedDict(sorted(d.items()))
    #腰至少存在两个
    waist , edges = {k: v for k, v in d.items() if v>1}, list(d.keys())
    length = len(edges)
    total = 0
    for w,n in waist.items():
        times = n*(n-1)/2
        # 有序遍历所有边
        for i in range(0,length):
            edge1 = edges[i] 
            num1 = d[edge1]
            if edge1 == w:
                if num1 > 2:
                    # 三个边相等
                    num1 = (n-2)/3
                else:
                    continue
            # 遍历最长边
            for j in range(i+1,length):
                edge2 = edges[j]
                num2 = d[edge2]
                if edge1 + w + w <= edge2:
                    #最长边大于其他三个边之和
                    break
                if edge2 == w:
                    num2 = (n-2)/3
                total += times*num1*num2
    return int(total)

if __name__ == "__main__":
    testcases = int(input())
    for caseNr in range(1, testcases+1):
        n=input()
        data = [int(i) for i in input().split()]
        print("Case #%i: %s" % (caseNr, get_isosceles_trapezoid_num(data)))