题解 | #合并表记录#

a = int(input())
dic = {}
for i in range(a):
    tem = input().split( )
    index = int(tem[0])
    value = int(tem[1])
    if index in dic:##直接判断引索字符串在不在字典里
        dic[index] = dic[index] + value
    else:
        dic[index] = value
# print(sorted(dic.items()))     [(0, 3), (1, 2), (3, 4)]#sorted帮你转变成列表
# print(type((dic.items())))      <class 'dict_items'>
# print(dic.items())                  dict_items([(0, 3), (1, 2), (3, 4)])
for w in sorted(dic.items()):
    print(w[0],w[1])