#include <bits/stdc++.h> using namespace std; struct block { int st, ed, th; } f,x,ad; int n, cnt, t[200002]; queue<block> q, q2; bool used[200001]; int main() { scanf("%d", &n); for (int i = 1; i <= n; i ++)scanf("%d", &t[i]); t[n + 1] = !t[n]; for (int i = 2, si = 1; i <= n + 1; i ++) { if (t[i] != t[i - 1]) q.push((block) { si, i - 1, t[i - 1] }), si = i; } cnt = n; while (cnt) { while (q.size()) { f = q.front(); q.pop(); while (used[f.st] && f.st <= f.ed) f.st ++; if (f.st > f.ed) continue; printf("%d ", f.st), cnt --; used[f.st] = 1; if (f.ed == f.st) continue; f.st ++; q2.push(f); } putchar('\n'); while (q2.size()) { ad = q2.front(); q2.pop(); while (q2.size()) { x = q2.front(); if (x.th == ad.th) { ad.ed = x.ed; q2.pop(); } else break; } q.push(ad); } } }