最大化(区间min * 区间和)

使用单调栈，从某一元素i向左右区间延伸，找到最大区间。
单调队列模板题

系统学习单调栈和单调队列戳：单调队列和单调栈详解
https://endlesslethe.com/monotone-queue-and-stack-tutorial.html

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

const int MAXN = 1000000 + 50;
int mq[MAXN], q[MAXN];

int T, x, index, front, r, l;
char input[10];

int main() {
    ios_base::sync_with_stdio(0);cin.tie(0);
    #ifdef LOCAL
        //freopen("in.txt","r",stdin);
        //freopen("out.txt","w",stdout);
    #endif
    scanf("%d", &T);
    while (T--) {
        index = front = r = l = 0;
        scanf("%s", input);
        while (scanf("%s", input) == 1) {
            if (input[0] == 'E') break;
            if (input[0] == 'C') {
                scanf("%s%d", input, &x);
                while (l != r && mq[r] <= x) r--;
                mq[++r] = x; 
                q[r] = ++index;
            }
            else if (input[0] == 'Q') {
                if (l != r) printf("%d\n", mq[l+1]);
                else printf("-1\n");
            }
            else if (input[0] == 'G') {
                if (front < index) front++;
                if (l != r && front == q[l+1]) l++;
            }

        }
    }
    return 0;
}