50221. Pascal's triangle

#include <stdio.h>
#include <stdlib.h>
#include "Pascal.h"
 
// typedef struct node {
//     int value;
//     struct node *left;
//     struct node *right;
// } Node;
 
void dfs(Node* n){
    if(n == NULL) return;
    n->value += 1;
    dfs(n->left);
    dfs(n->right);
}
 
void build_Pascal(Node* arr, int height){
    int n = (height) * (height + 1) / 2;
    for(int i = 0; i < n; i++) arr[i].value = 0;
 
    // right ptrs
    for(int i = 0; i < n - 1; i++){
        arr[i].right = &arr[i + 1];
    }
 
    // left ptrs
    int cnt = 0;
    int d = height;
    for(int i = 0; i < n - 1; i++){
        if(i + d < n) arr[i].left = &arr[i + d];
        cnt++;
        if(cnt == d) cnt = 0, d--;
    }
 
    // remove leaves
    int now = -1;
    for(int i = height; i > 0; i--){
        now += i;
        arr[now].right = NULL;
        arr[now].left = NULL;
    }
 
    dfs(&arr[0]);
}