CUBE-079: The Exam Sort

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

int main(){

    int n;
    scanf("%d",&n);
    vector <int> num{0};
    set <int> keep;

    for(int i=1;i<=n;i++){
        int x;
        scanf("%d",&x);
        num.push_back(x);
    }

    int s = 1, e = n, cnt = 0;
    for(int j=1;j<=n;j++){
        int x;
        if(j%2 == 1) {
            x = s;
            s++;
        }
        else {
            x = e;
            e--;
        }
        if(num[x] == x) {
            cnt++;
            continue;
        }
        for(int j=1;j<=n;j++){
            if(num[j] == x){
                num.erase(num.begin()+j);
                num.insert(num.begin()+x,x);
                break;
            }
        }
    }

    printf("%d",cnt);

    return 0;
}