1 class Solution { 2 public: 3 void solve(vector<vector<char>> &board) { 4 int m = board.size(); 5 if(m == 0) 6 return; 7 int n = board[0].size(); 8 int i,j; 9 for(i=0;i<m;i++) 10 { 11 if (board[i][0]=='O') 12 bfs(i,0,board); 13 if (board[i][n-1]=='O') 14 bfs(i,n-1,board); 15 } 16 for(j=0;j<n;j++) 17 { 18 if (board[0][j]=='O') 19 bfs(0,j,board); 20 if (board[m-1][j]=='O') 21 bfs(m-1,j,board); 22 } 23 for(i=0;i<m;i++) 24 { 25 for(j=0;j<n;j++) 26 { 27 if(board[i][j]=='O') 28 board[i][j]='X'; 29 else if (board[i][j]=='E') 30 board[i][j]='O'; 31 } 32 } 33 } 34 void bfs(int i,int j,vector<vector<char>> &board){ 35 int m = board.size(); 36 int n = board[0].size(); 37 38 queue<pair<int,int> > Q; 39 Q.push(make_pair(i,j)); 40 board[i][j] = 'E'; 41 int dx[4] = {-1,0,0,1}; 42 int dy[4] = {0,-1,1,0}; 43 while(!Q.empty()){ 44 pair<int,int> p = Q.front(); 45 Q.pop(); 46 47 int iidx = p.first; 48 int jidx = p.second; 49 50 for(int i = 0 ; i < 4 ; ++i){ 51 int itmp = iidx+dx[i]; 52 int jtmp = jidx+dy[i]; 53 54 if((itmp < m && itmp >= 0)&&(jtmp < n && jtmp >= 0) && board[itmp][jtmp] == 'O'){ 55 Q.push(make_pair(itmp,jtmp)); 56 board[itmp][jtmp] = 'E'; 57 } 58 } 59 } 60 } 61 };
dfs和bfs都可以