Making_A_Large_Island.py

from typing import List
class Solution:
    def largestIsland(self, l: List[List[int]]) -> int:
        k,s=[],{}
        c,h=2,0
        n,m=len(l),len(l[0])
        def dfs(i,j,c):
            if l[i][j]==1:
                l[i][j]=c
                s[c]+=1
            if j<m-1 and l[i][j+1]==1:dfs(i,j+1,c)
            if i<n-1 and l[i+1][j]==1:dfs(i+1,j,c)
            if j>0 and l[i][j-1]==1:dfs(i,j-1,c)
            if i>0 and l[i-1][j]==1:dfs(i-1,j,c)
        for i in range(n):
            for j in range(m):
                if isinstance(l[i][j], int) and l[i][j]==1:
                    s[c]=0
                    dfs(i,j,c)
                    h=max(h,s[c]+1)
                    c+=1
        if h==0:return(1)
        def count(i,j):
            c,k=0,set()
            if j<m-1 and l[i][j+1]>1 and l[i][j+1] not in k:
                k.add(l[i][j+1])
                c+=s[l[i][j+1]]
            if i<n-1 and l[i+1][j]>1 and l[i+1][j] not in k:
                k.add(l[i+1][j])
                c+=s[l[i+1][j]]
            if j>0 and l[i][j-1]>1 and l[i][j-1] not in k:
                k.add(l[i][j-1])
                c+=s[l[i][j-1]]
            if i>0 and l[i-1][j]>1 and l[i-1][j] not in k:
                k.add(l[i-1][j])
                c+=s[l[i-1][j]]
            return(c)
        for i in range(n):
            for j in range(m):
                if l[i][j]==0:h=max(count(i,j)+1,h)
        return(min(h,m*n))

#{ 
 # Driver Code Starts

class IntMatrix:
    def __init__(self) -> None:
        pass
    def Input(self,n,m):
        matrix=[]
        #matrix input
        for _ in range(n):
            matrix.append([int(i) for i in input().strip().split()])
        return matrix
    def Print(self,arr):
        for i in arr:
            for j in i:
                print(j,end=" ")
            print()

if __name__=="__main__":
    t = int(input())
    for _ in range(t):
        
        n = int(input())
        
        grid=IntMatrix().Input(n,n)
        
        obj = Solution()
        res = obj.largestIsland(grid)
        
        print(res)
# } Driver Code Ends