oct_7.js

function nQueenPlacement(board) {
  let rowPositions = [];
  let colPositions = [];
  for (let i = 0; i < board.length; i++) {
    for (let j = 0; j < board[i].length; j++) {
      if (board[i][j] === 1) {
        if (rowPositions.indexOf(i) === -1 && colPositions.indexOf(j) === -1 && pairModulusDiffers(rowPositions, colPositions, i, j)) {
          rowPositions.push(i);
          colPositions.push(j);
        }
        else { return false; }
      }
    }
  }
  return true;
}
function pairModulusDiffers(rowPositions, colPositions, row, col) {
  for (let i = 0; i < rowPositions.length; i++) {
    if (Math.abs(rowPositions[i] - row) === Math.abs(colPositions[i] - col)) {
      return false;
    }
  }
  return true;
}

function join(wordsArr) {
  let min = Infinity
  while (wordsArr.length > 1) {
    const merged = mergeWords(wordsArr.shift(), wordsArr.shift())
    wordsArr.unshift(merged[0])
    min = Math.min(merged[1], min)
  }

  return [wordsArr[0], min]
}

function mergeWords(word1, word2) {
  let ctr = 0;
  for (let i = 0; i < Math.min(word2.length, word1.length); i++) {
    let z = word1.substring(word1.length - 1 - i)
    let x = word2.substring(0, i + 1)
    if (word1.substring(word1.length - 1 - i) === word2.substring(0, i + 1)) ctr = i
  }
  return [word1.substring(0, word1.length - 1 - ctr + 1) + word2.substring(ctr), ctr + 1]
}


console.log(join(["oven", "envier", "erase", "serious"])) //➞ ["ovenvieraserious", 2]