python/TangDou/LanQiaoBei/ZhongGaoJi/LanQiao14STEMA202301/TD.cpp

#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const int N = 110;
double a[N];
int n;
int f1[N], f2[N];
int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 1; i <= n; i++) {
        f1[i] = 1;
        for (int j = 1; j < i; j++)
            if (a[i] > a[j]) f1[i] = max(f1[i], f1[j] + 1);
    }
    for (int i = n; i >= 1; i--) {
        f2[i] = 1;
        for (int j = 1; j < i; j++)
            if (a[i] > a[j]) f2[i] = max(f1[i], f1[j] + 1);
    }
    bool flag = true;
    for (int i = 1; i <= n; i++)
        if (f1[i] != 1) {
            flag = false;
            break;
        }
    if (flag) {
        cout << -1 << endl;
        exit(0);
    }
    flag = true;
    for (int i = 1; i <= n; i++)
        if (f2[i] != 1) {
            flag = false;
            break;
        }
    if (flag) {
        cout << -1 << endl;
        exit(0);
    }
    int mx = -1;
    for (int i = 1; i <= n; i++){
        int t = f1[i] + f2[i];
        mx = max(mx, t);
    }
    cout << n - mx + 1;
    return 0;
}