0036-valid-sudoku.cs

publicclassSolution{
publicboolIsValidSudoku(char[][]board){
varrows=newDictionary<int,HashSet<char>>();
varcols=newDictionary<int,HashSet<char>>();
varsquares=newDictionary<(int,int),HashSet<char>>();

for(varr=0;r<9;r++){
rows[r]=newHashSet<char>();
for(varc=0;c<9;c++){
if(!cols.ContainsKey(c))cols[c]=newHashSet<char>();
if(!squares.ContainsKey((r/3,c/3)))
squares[(r/3,c/3)]=newHashSet<char>();

if(board[r][c]=='.')continue;


if(rows[r].Contains(board[r][c])||
cols[c].Contains(board[r][c])||
squares[(r/3,c/3)].Contains(board[r][c]))
returnfalse;

rows[r].Add(board[r][c]);
cols[c].Add(board[r][c]);
squares[(r/3,c/3)].Add(board[r][c]);
}
}

returntrue;
}
}