Submission #798221

#	Time	Username	Problem	Language	Result	Execution time	Memory
798221		hungnt	Non-boring sequences (CERC12_D)	C++14	1 / 1	284 ms	17096 KiB

D

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

const int N = 200005;

int n;
int a[N], b[N], pos[N];
int low[N], high[N];

bool boring(int L, int R)
{
    if(L >= R) return 0;
    int curL = L, curR = R;
    bool x = 0;
    while(curL <= curR)
    {
        if (!x)
        {
            if (low[curL] < L && high[curL] > R)
            return boring(L, curL - 1) || boring(curL + 1, R);
            ++curL;
        }
        else {
          if (low[curR] < L && high[curR] > R)
            return boring(L, curR - 1) || boring(curR + 1, R);
          --curR;
        }
        x ^= 1;
    }
    return 1;
}


void process()
{
    cin >> n;
    for(int i = 1; i <= n; i++)
    {
        cin >> a[i];
        b[i] = a[i];
    }
    sort(b + 1, b + n + 1);
    for(int i = 1; i <= n; i++) a[i] = lower_bound(b + 1, b + n + 1, a[i]) - b;
    for(int i = 1; i <= n; i++) pos[i] = 0;
    for(int i = 1; i <= n; i++)
    {
        low[i] = pos[a[i]];
        pos[a[i]] = i;
    }
    for(int i = 1; i <= n; i++) pos[i] = n + 1;
    for(int i = n; i >= 1; i--)
    {
        high[i] = pos[a[i]];
        pos[a[i]] = i;
    }
    cout << (boring(1, n) ? "boring\n" : "non-boring\n");
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int t;
    cin >> t;
    while(t--) process();
    return 0;
}

• Subtask 1: 1 / 1