第一题：求乘4后，是逆序的数 AC

N = int(input())
res = []
for i in range(1,N//4+1):
    ni = i*4
    if str(i)[::-1]==str(ni) and ni<=N:
        res.append([i,ni])
print(len(res))
for i in res:
    print(i[0],i[1]) 

第二题：求旅游次数，19% 求大佬解答哪里错了，不是就一行行统计就完了

N = int(input())
falg = True
count = 0
for i in range(N):  
    tmp = input().split()
    if falg==True:
        start = tmp[0]
        nxt = tmp[1]
        falg = False
    else:
        if tmp[0]==nxt:
            nxt = tmp[1]
        if nxt==start:
            count += 1 
            falg = False
print(count)

第三题：题意忘了，思路dfs 遍历把一个小区的放一起，然后排序 55%

tmp = input().split()
n,m = int(tmp[0]),int(tmp[1])
from collections import defaultdict
dic = defaultdict(list)
for i in range(m):
    t = input().split()
    a,b = int(t[0]),int(t[1])
    if b not in dic[a]:
        dic[a].append(b)
    if a not in dic[b]:
        dic[b].append(a)

visited=[]
res = defaultdict(list)
count=0
for i in range(1,n+1):
    if i not in visited:
        sub = []
        stack = [i]
        while stack:
            cur = stack.pop(-1)
            for v in dic[cur]:
                if v not in visited: 
                    stack.append(v)
            visited.append(cur)
            sub.append(cur)
        res[count].append(list(set(sub)))
        count += 1
print(count)
res_ = sorted(res.items(),key=lambda x:x[1][0])

for i in range(len(res_)):
    res = sorted(res_[i][1][0])
    for j in res:
        print(j,end=' ')
    print(' ')

第四题: 打扰了，两个背包，好像要三维dp 没时间了

求大佬指出错误，或者python AC的代码评论一下，咱们一起进步。