The Second Run of Quicksort

代码

#include<iostream>
#include<vector>
#include<cstdio>
using namespace std;
const int maxn = 100010;
vector<int> sequence;
int maxL, minR, cnt, k, n, tmp;
bool bigger[maxn];
bool pivot[maxn];
int main()
{
    cin >> k;
    while (k--)
    {
        scanf("%d", &n);
        sequence.clear();
        for (int i = 0; i < n; i++)
        {
            scanf("%d", &tmp);
            sequence.emplace_back(tmp);
        }
        fill(bigger, bigger + n, false);
        fill(pivot, pivot + n, false);
        maxL = -1, minR = 0x3fffffff;
        cnt = 0;
        for (int i = 0; i < n; i++)
        {
            if (sequence[i] > maxL)
            {
                bigger[i] = true;
                maxL = sequence[i];
            }
        }
        for (int i = n - 1; i >= 0; i--)
        {
            if (bigger[i] && sequence[i] < minR)
            {
                cnt++;
                pivot[i] = true;
                if (cnt == 3) break;
            }
            if (sequence[i] < minR)minR = sequence[i];
        }
        if (cnt >= 3) cout << "Yes" << endl;
        else if (cnt == 2 && (pivot[0] || pivot[n - 1]))cout << "Yes" << endl;
        else cout << "No" << endl;

    }
}