1 const int dx[] = {
   1,-1,0,0}; 2 const int dy[] = {
   0,0,1,-1}; 3 #define _for(i,a,b) for(int i = (a);i < (b);i ++) 4 class Solution 5 { 6     public: 7         int vis[60][60]; 8         void go(vector
     
      
       >& grid, int r0, int c0, int color,int lo) 9         {10             vis[r0][c0] = 1;11             grid[r0][c0] = -color;12             _for(i,0,4)13             {14                 int nx = r0 + dx[i];15                 int ny = c0 + dy[i];16                 if(nx>=0 && nx
       
        =0 && ny
        

> colorBorder(vector

>& grid, int r0, int c0, int color)24 {25 memset(vis,0,sizeof(vis));26 int lo = grid[r0][c0];27 go(grid,r0,c0,color,lo);28 vector

> vv;29 _for(i,0,grid.size())30 _for(j,0,grid[i].size())31 if(grid[i][j]<0)32 {33 if(i==0 || i==grid.size()-1 || j==0 || j==grid[i].size()-1)34 continue;35 if(grid[i+1][j]==-color && grid[i-1][j]==-color && grid[i][j+1]==-color && grid[i][j-1]==-color)36 vv.push_back({i,j});37 // grid[i][j] = lo;38 }39 _for(i,0,vv.size())40 grid[vv[i].first][vv[i].second] = lo;41 _for(i,0,grid.size())42 _for(j,0,grid[i].size())43 {44 if(grid[i][j]<0)45 grid[i][j] = -grid[i][j];46 }47 48 return grid;49 }50 };