SOURCE

//并查集
    //初始化
    let board =[["O","O","O"],["O","O","O"],["O","O","O"]]
    let row = board.length;
    let column = board[0].length;
    let arr = [];
    for(let i = 0; i < row * column; i++) {
        arr[i] = i;
    }
    //查找
    function lookup(index) {
        if(arr[index] == index) {
            return index
        }else {
            lookup(arr[index])
        }
    }
    //合并
    function merge(index1, index2) {
        let temp1 = lookup(index1);
        let temp2 = lookup(index2);
        arr[temp1] = arr[temp2];
    }
    for(let i = 0; i < row; i++) {
        for(let j = 0; j < column; j++) {
            let temp = i * column + j;
            if(board[i][j] == 'O') {
                if(j - 1 > 0 && board[i][j - 1] == 'O') {
                    // let temp: number = i * column + j; 
                    merge(temp - 1, temp);
                }
                if(i - 1 > 0 && board[i - 1][j] == 'O') {
                    // let temp: number = i * column + j;
                    merge(temp - column, temp)
                }
            }else {
                arr[temp] = undefined
            }
        }
    }
    console.log(arr)
    arr.forEach((item, index) => {
        if(item != undefined) {
            console.log(index)
            if(index < column || index >= (row - 1) * column || index % column == 0 || index % column == column - 1) {
                console.log(index, 0)
                sign(index)
            }
        }
    })
    function sign(index) {
        let i = Math.floor(index / column);
        let j = index % column;
        console.log(i,j,arr[index])
        board[i][j] = 'A';
        if(index != arr[index]) {
            sign(arr[index]);
        }
        if(arr.indexOf(index) != index) {
            sign(arr.indexOf(index))
        }
    }