UVA - 1608 Non-boring sequences （分治）

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cctype>
#include<cmath>
#include<iostream>
#include<sstream>
#include<iterator>
#include<algorithm>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<stack>
#include<deque>
#include<queue>
#include<list>
#define lowbit(x) (x & (-x))
const double eps = 1e-8;
inline int dcmp(double a, double b){
    if(fabs(a - b) < eps) return 0;
    return a > b ? 1 : -1;
}
typedef long long LL;
typedef unsigned long long ULL;
const int INT_INF = 0x3f3f3f3f;
const int INT_M_INF = 0x7f7f7f7f;
const LL LL_INF = 0x3f3f3f3f3f3f3f3f;
const LL LL_M_INF = 0x7f7f7f7f7f7f7f7f;
const int dr[] = {0, 0, -1, 1, -1, -1, 1, 1};
const int dc[] = {-1, 1, 0, 0, -1, 1, -1, 1};
const int MOD = 1e9 + 7;
const double pi = acos(-1.0);
const int MAXN = 200000 + 10;
const int MAXT = 10000 + 10;
using namespace std;
int a[MAXN], l[MAXN], r[MAXN];
map<int, int> mp;
bool solve(int L, int R){
    if(L >= R) return true;
    for(int i = 0; i <= (R - L) / 2; ++i){
        if(l[L + i] < L && r[L + i] > R){
            return solve(L, L + i - 1) && solve(L + i + 1, R);
        }
        if(l[R - i] < L && r[R - i] > R){
            return solve(L, R - i - 1) && solve(R - i + 1, R);
        }
    }
    return false;
}
int main(){
    int T;
    scanf("%d", &T);
    while(T--){
        int n;
        scanf("%d", &n);
        for(int i = 0; i < n; ++i){
            scanf("%d", &a[i]);
        }
        mp.clear();
        for(int i = 0; i < n; ++i){
            if(!mp.count(a[i])) l[i] = -1;
            else l[i] = mp[a[i]];
            mp[a[i]] = i;
        }
        mp.clear();
        for(int i = n - 1; i >= 0; --i){
            if(!mp.count(a[i])) r[i] = n;
            else r[i] = mp[a[i]];
            mp[a[i]] = i;
        }
        bool ok = solve(0, n - 1);
        if(ok){
            printf("non-boring\n");
        }
        else{
            printf("boring\n");
        }
    }
    return 0;
}