Binary tree postorder -> structure

gistfile1.c

#include <stdio.h>

void printTree(int *idx, int *post, int rootIdx, int n) {
    int root = post[rootIdx];

    printf("%d", root);

    if(root == n-1 || idx[root+1] > rootIdx) return;
    
    printf(" { ");
        printTree(idx, post, idx[root+1], n);
    printf(" ; ");
        printTree(idx, post, rootIdx - 1, n);
    printf(" }");
}

int main() {
    int post[] = {2,3,1,6,7,5,8,4,0};
    const int n = sizeof(post)/sizeof(*post);
    int idx[n], i;

    for(i = 0; i < n; ++i) idx[post[i]] = i;
    printTree(idx, post, n-1, n);

    return 0;
}