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<vector<int>>& 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<grid.size() && ny>=0 && ny<grid[0].size()
17 && vis[nx][ny]==0 && grid[nx][ny]==lo)
18 {
19 go(grid,nx,ny,color,lo);
20 }
21 }
22 }
23 vector<vector<int>> colorBorder(vector<vector<int>>& 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<pair<int,int>> 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 };
