Python代码

n=int(input())
m=[]
for i in range(n):
    m.append(list(input()))
dx=[-1,0,1,0]
dy=[0,1,0,-1]
st=[[True for _ in range(n)]for _ in range(n)]
arr=[]
res=0
def dfs(x,y):
    global res
    if len(arr)%2==0:
        flag=1
        t=len(arr)//2
        for i in range(len(arr)):
            if i<t:
                if arr[i]==")":
                    flag=0
            if i>=t:
                if arr[i]=="(":
                    flag=0
        if flag==1:
            res=max(res,len(arr))


    for i in range(4):
        a=x+dx[i]
        b=y+dy[i]
        if a>=0 and a<n and b>=0 and b<n and st[a][b]:
            st[a][b]=False
            arr.append(m[a][b])
            dfs(a,b)
            st[a][b]=True
            arr.pop()
st[0][0]=False
arr.append(m[0][0])
dfs(0,0)
print(res)