JS遞歸實現楊輝三角

/* 1 1 1 1 2 1 ... 輸入 n ,輸出數組 假設輸入 3，輸出數組 [[1],[1,1],[1,2,1]] */ function triangle(num){ let arr = []; arr.push([1]); loop([1]); function loop(lastarr){ if(lastarr.length < num){ let newarr = []; newarr[0] = 1; newarr[lastarr.length] = 1; for(let i = 0; i < lastarr.length-1; i++){ newarr[i+1] = lastarr[i] + lastarr[i+1]; } arr.push(newarr); loop(newarr); } } return arr; } console.log(triangle(5));