0130-surrounded-regions.ts

/**
 Do not return anything, modify board in-place instead.
 */
functionsolve(board: string[][]): void{
constrowLen=board.length;
constcolLen=board[0].length;
constlastRow=rowLen-1;
constlastCol=colLen-1;

for(letr=0;r<rowLen;++r){
markSeen(r,0);
markSeen(r,lastCol);
}
for(letc=1;c<lastCol;++c){
markSeen(0,c);
markSeen(lastRow,c);
}

for(letr=0;r<rowLen;++r){
for(letc=0;c<colLen;++c){
switch(board[r][c]){
case'O':
board[r][c]='X';
break;
case'A':
board[r][c]='O';
break;
}
}
}

functionmarkSeen(r: number,c: number): void{
if(!inBounds(r,c)||board[r][c]!=='O'){
return;
}

board[r][c]='A';

markSeen(r-1,c);
markSeen(r+1,c);
markSeen(r,c-1);
markSeen(r,c+1);
}

functioninBounds(r: number,c: number): boolean{
returnr>=0&&c>=0&&r<rowLen&&c<colLen;
}
};