python/TangDou/CSP-J/J2-2021/4_Queue_AC.cpp

#include <bits/stdc++.h>
using namespace std;
const int N = 200010;

struct Node {
    int l, r, v;
};

int w[N];
bool st[N];
int n;
queue<Node> q, p;

int main() {
    scanf("%d", &n);
    for (int i = 1; i <= n; i++) scanf("%d", &w[i]);

    w[n + 1] = 2;
    for (int i = 1, start = 1; i <= n; i++)
        if (w[i] != w[i + 1]) {
            q.push({start, i, w[i]});
            start = i + 1;
        }

    int cnt = 0;
    while (cnt < n) {
        while (q.size()) {
            auto a = q.front();
            q.pop();
            
            while (st[a.l] && a.l <= a.r) a.l++;
            if (a.l > a.r) continue;

            printf("%d ", a.l);
            cnt++;
            st[a.l] = true;
            a.l++;
            if (a.l > a.r) continue;
            p.push(a);
        }

        while (p.size()) {
            auto a = p.front();
            p.pop();

            while (p.size()) {
                auto b = p.front();
                if (b.v == a.v) {
                    a.r = b.r;
                    p.pop();
                } else
                    break;
            }
            q.push(a);
        }
        puts("");
    }
    return 0;
}