Create 529.Minesweeper.cpp

Author: wisdompeak

BFS/529.Minesweeper/529.Minesweeper.cpp

@@ -0,0 +1,55 @@
+class Solution {
+public:
+    vector<vector<char>> updateBoard(vector<vector<char>>& board, vector<int>& click) 
+    {
+        int M = board.size();
+        int N = board[0].size();
+        if (board[click[0]][click[1]]=='M')
+        {
+            board[click[0]][click[1]] = 'X';
+            return board;
+        }
+        
+        auto dir = vector<pair<int,int>>({{1,0},{1,1},{0,1},{-1,1},{-1,0},{-1,-1},{0,-1},{1,-1}});
+        set<pair<int,int>>visited;
+        
+        queue<pair<int,int>>q;
+        q.push({click[0],click[1]});
+        visited.insert({click[0],click[1]});
+        
+        while (!q.empty())
+        {
+            int i = q.front().first;
+            int j = q.front().second;
+            q.pop();
+            
+            vector<pair<int,int>>next;
+            int count = 0;
+            for (int k=0; k<8; k++)
+            {
+                int x = i+dir[k].first;
+                int y = j+dir[k].second;
+                if (x<0||x>=M||y<0||y>=N) continue;
+                if (board[x][y]!='E' && board[x][y]!='M') continue;
+                                
+                if (board[x][y]=='M') count++;
+                else if (visited.find({x,y})==visited.end())
+                    next.push_back({x,y});
+            }
+            
+            if (count>0)            
+                board[i][j]=count+'0';                            
+            else
+            {
+                board[i][j]='B';
+                for (auto p:next)
+                {
+                    q.push(p);
+                    visited.insert(p);
+                }                    
+            }
+        }
+        
+        return board;
+    }
+};