36 solved

code.cpp

@@ -99,4 +99,40 @@ int searchInsert(vector<int>& nums, int target) {
 		}
 	}
 	return nums.size();
-}
\ No newline at end of file
+}
+
+
+// 36 Valid Sudoku
+// an easy median problem, used set to deal with the repeated num problem
+// not fast, but works
+bool isValidSudoku(vector<vector<char>>& board) {
+	vector<set<char> > rows;
+	vector<set<char> > cols;
+	vector<set<char> > boxs;
+
+	rows.resize(9);
+	cols.resize(9);
+	boxs.resize(9);
+
+	for(int r=0; r<9; r++){
+		for(int c=0; c<9; c++){
+			if(board[r][c] != '.'){
+
+				int box_index = (r/3) * 3 + c/3;
+
+				if( rows[r].find((board[r][c])) == rows[r].end() &&
+				cols[c].find((board[r][c])) == cols[c].end() &&
+				boxs[box_index].find(board[r][c]) == boxs[box_index].end()){
+					rows[r].insert(board[r][c]);
+					cols[c].insert(board[r][c]);
+					boxs[box_index].insert(board[r][c]);
+				}
+				else{
+					return false;
+				}
+			}
+
+		}
+	}
+	return true;
+}