#include "gift.h"
#include <set>
using namespace std;
int construct(int n, int r, std::vector<int> a, std::vector<int> b, std::vector<int> x) {
string ans(n, 'R');
vector<int> a_(n);
set<int> s;
for (int i = 0; i < n; ++i)
s.insert(i);
for (int i = 0; i < r; ++i)
if (x[i] == 1) {
auto it = s.lower_bound(a[i]);
if (it == s.end() || *it > a[i])
--it;
auto itr = s.upper_bound(b[i]);
s.erase(next(it), itr);
}
for (int i = 0; i < r; ++i)
if (x[i] == 2) {
auto it = s.lower_bound(a[i]);
if (it == s.end() || *it > a[i]) --it;
auto it2 = s.lower_bound(b[i]);
if (it2 == s.end() || *it2 > b[i])
--it2;
if (it == it2) {
return 0;
}
}
for (auto x : s) a_[x] ^= 1;
for (int i = 0, run = 0; i < n; ++i) {
run ^= a_[i];
ans[i] = run ? 'R' : 'B';
}
craft(ans);
return 1;
}
