Stack Exchange network consists of 183 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.
Visit Stack Exchange
Stack Internal
Knowledge at work
Bring the best of human thought and AI automation together at your work.
Explore Stack Internal
f= n=>[...Array(n+--n)].map(g=(j=n,i,a)=>j--?g(j,i-1)+g(j,i+1)+(a?g(j,i,a):0):i-n?0:1)<input type=number min=1 oninput=o.textContent=f(+this.value)><pre id=o> 1-indexing cost me a byte. Explanation: g(j-1,i-1)+g(j-1,i+1) recursively calculates Pascal's triangle until it reaches the first row, which is the base case. To obtain column sums, I use the fact that map actually passes a third parameter, so there is an extra recursive step when this is the case.
f= n=>[...Array(n+--n)].map(g=(j=n,i,a)=>j--?g(j,i-1)+g(j,i+1)+(a?g(j,i,a):0):i-n?0:1)<input type=number min=1 oninput=o.textContent=f(+this.value)><pre id=o>1-indexing cost me a byte.
f= n=>[...Array(n+--n)].map(g=(j=n,i,a)=>j--?g(j,i-1)+g(j,i+1)+(a?g(j,i,a):0):i-n?0:1)<input type=number min=1 oninput=o.textContent=f(+this.value)><pre id=o> 1-indexing cost me a byte. Explanation: g(j-1,i-1)+g(j-1,i+1) recursively calculates Pascal's triangle until it reaches the first row, which is the base case. To obtain column sums, I use the fact that map actually passes a third parameter, so there is an extra recursive step when this is the case.