Leetcode-827 Making A Large Island(最大人工岛)

int x[] = {1,-1,0,0};
int y[] = {0,0,1,-1};

class Solution
{
    private:
        int acreList[1500];
        int acreListEnd;
        int Maxresult;
        int rowSize;
        int colSize;
    public:
        int largestIsland(vector<vector<int>>& grid)
        {
            acreListEnd = 2;
            acreList[0] = 0;
            Maxresult = 1;
            rowSize = grid.size();
            colSize = grid[0].size();
            for(int i = 0;i < grid.size();i ++)
            {
                for(int j = 0;j < grid[0].size();j ++)
                {
                    int tmpAcre = 0;
                    if(grid[i][j] == 1)
                    {
                        preDfs(i,j,grid,tmpAcre);
                        acreList[acreListEnd ++] = tmpAcre;
                    }
                }
            }
            
            /*
            for(int i = 0;i < rowSize;i ++)
            {
                for(int j = 0;j < colSize;j ++)
                {
                    cout << grid[i][j] << " " ;
                }
                cout << endl;
            }
            */
        //    cout << acreList[3] << endl;
        //    memset(0,visit,sizeof(visit));
            int flag = 0;
            for(int i = 0;i < grid.size();i ++)
            {
                for(int j = 0;j < grid[0].size();j ++)
                {
                    if(grid[i][j] == 0)
                    {
                        Dfs(i,j,grid);
                        flag = 1;
                    }
                }
            }
            if(!flag)
                Maxresult = rowSize*colSize;
            return Maxresult;
        }
        bool limit(int a,int b)
        {
            return (a>=0 && a<rowSize && b>=0 && b<colSize);
        }
        void preDfs(int curX,int curY,vector<vector<int>>& grid,int &acre)
        {
            acre ++;
            grid[curX][curY] = acreListEnd;
            for(int i = 0;i < 4;i ++)
            {
                if(limit(curX+x[i],curY+y[i]) && grid[curX+x[i]][curY+y[i]] == 1)
                {
                    preDfs(curX+x[i],curY+y[i],grid,acre);
                }
            }
        }
        void Dfs(int curX,int curY,vector<vector<int>> grid)
        {
            int result[4] = {0};
            for(int i = 0;i < 4;i ++)
            {
                int flag = 1;
                if(limit(curX+x[i],curY+y[i]))
                {
                    for(int j = 0;j < i;j ++)
                    {
                        if(result[j]==grid[curX+x[i]][curY+y[i]])
                        {
                            flag = 0;
                            break;
                        }
                    }
                    if(flag)
                        result[i] = grid[curX+x[i]][curY+y[i]];
                    else
                        result[i] = 0;
                }
                else
                    result[i] = 0;
            }
            for(int i = 0;i < 4;i ++)
                result[i] = acreList[result[i]];
            sort(result,result+4);
            if(result[0]+result[1]+result[3]+result[2]+1>Maxresult)
            {
                Maxresult = result[0]+result[1]+result[3]+result[2]+1;
            }
            cout << result[2] << " " << result[3] << endl;
        }
};