如果至少有一个值相等，则合并二维数组的行

function mergeRows(arr) {
  for (let i = 0; i < arr.length; i++) {
    for (let j = i + 1; j < arr.length; j++) {
      let isEqual = false;
      for (let k = 0; k < arr[i].length; k++) {
        if (arr[i][k] === arr[j][k]) {
          isEqual = true;
          break;
        }
      }
      if (isEqual) {
        let mergedRow = arr[i].concat(arr[j]);
        arr.splice(j, 1);
        arr.splice(i, 1);
        arr.push(mergedRow);
        i--;
        break;
      }
    }
  }
  return arr;
}

// 示例用法
let arr = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9],
  [1, 2, 3]
];
let mergedArr = mergeRows(arr);
console.log(mergedArr);