|
| 1 | +////////////////////////////////////////////////////////////////////////////// |
| 2 | +// Depth First Search (DFS) |
| 3 | +// Time: O(m*n) |
| 4 | +// Space: O(m*n) |
| 5 | +// You can implement either Depth First Search (DFS) or Breadth First Search |
| 6 | +// (BFS). The only noticeable impact is the performance cost of the BFS queue |
| 7 | +// is higher than the DFS call stack. |
| 8 | +////////////////////////////////////////////////////////////////////////////// |
| 9 | + |
| 10 | +/** |
| 11 | + *@param {character[][]} board |
| 12 | + *@return {void} Do not return anything, modify board in-place instead. |
| 13 | + */ |
| 14 | +functionsolve(board){ |
| 15 | + |
| 16 | +constrowLen=board.length; |
| 17 | +constcolLen=board[0].length; |
| 18 | +constlastRow=rowLen-1; |
| 19 | +constlastCol=colLen-1; |
| 20 | + |
| 21 | +for(letr=0;r<rowLen;++r){ |
| 22 | +markSeen(r,0); |
| 23 | +markSeen(r,lastCol); |
| 24 | +} |
| 25 | +for(letc=1;c<lastCol;++c){ |
| 26 | +markSeen(0,c); |
| 27 | +markSeen(lastRow,c); |
| 28 | +} |
| 29 | + |
| 30 | +for(letr=0;r<rowLen;++r){ |
| 31 | +for(letc=0;c<colLen;++c){ |
| 32 | +switch(board[r][c]){ |
| 33 | +case'O': |
| 34 | +board[r][c]='X'; |
| 35 | +break; |
| 36 | +case'A': |
| 37 | +board[r][c]='O'; |
| 38 | +break; |
| 39 | +} |
| 40 | +} |
| 41 | +} |
| 42 | + |
| 43 | +/** |
| 44 | + *@param {number} r |
| 45 | + *@param {number} c |
| 46 | + *@return {void} |
| 47 | + */ |
| 48 | +functionmarkSeen(r,c){ |
| 49 | + |
| 50 | +if(!inBounds(r,c)||board[r][c]!=='O'){ |
| 51 | +return; |
| 52 | +} |
| 53 | + |
| 54 | +board[r][c]='A'; |
| 55 | + |
| 56 | +markSeen(r-1,c); |
| 57 | +markSeen(r+1,c); |
| 58 | +markSeen(r,c-1); |
| 59 | +markSeen(r,c+1); |
| 60 | +} |
| 61 | + |
| 62 | +/** |
| 63 | + *@param {number} r |
| 64 | + *@param {number} c |
| 65 | + *@return {boolean} |
| 66 | + */ |
| 67 | +functioninBounds(r,c){ |
| 68 | +returnr>=0&&c>=0&&r<rowLen&&c<colLen; |
| 69 | +} |
| 70 | +} |