MLE 求助

B3656 【模板】双端队列 1

#include <bits/stdc++.h>
using namespace std;

const int N = 1e6+10;
int n, a, x;
string s;
deque<int> q[N];

int main() {
	scanf("%d", &n);
	while(n--) {
		cin >> s;
		scanf("%d", &a);
		if(s == "push_back") {
			scanf("%d", &x);
			q[a].push_back(x);
		} else if(s == "pop_back") {
			if(q[a].empty()) continue;
			q[a].pop_back();
		} else if(s == "push_front") {
			scanf("%d", &x);
			q[a].push_front(x);
		} else if(s == "pop_front") {
			if(q[a].empty()) continue;
			q[a].pop_front();
		} else if(s == "size") {
			printf("%d\n", q[a].size());
		} else if(s == "front") {
			if(q[a].empty()) continue;
			printf("%d\n", q[a].front());
		} else {
			if(q[a].empty()) continue;
			printf("%d\n", q[a].back());
		}
	}
	return 0;
}