#include "gift.h"
#include <bits/stdc++.h>
using namespace std;
int construct(int n, int r, vector<int> a, vector<int> b, vector<int> x) {
vector<pair<int, int>> one, two;
for (int i = 0; i < r; i++) {
if (x[i] == 1) {
one.push_back(make_pair(a[i], b[i]));
} else {
two.push_back(make_pair(a[i], b[i]));
}
}
sort(one.begin(), one.end());
string s(n, '$');
int sid = 0;
char chr = 'R';
for (int i = 0; i < n; ) {
s[i] = chr;
if (sid < one.size() && one[sid].first <= i) {
while (i < n && i <= one[sid].second) {
s[i] = s[one[sid].first];
i++;
}
sid++;
} else {
i++;
}
chr = (chr == 'R' ? 'B' : 'R');
}
vector<int> pre(n);
for (int i = 1; i < n; i++) {
pre[i] = pre[i - 1] + (s[i] != s[i - 1]);
}
for (auto &[l, r] : two) {
if (pre[l] == pre[r]) {
return 0;
}
}
for (auto &[l, r] : one) {
assert(pre[l] == pre[r]);
}
for (auto &[l, r] : two) {
assert(pre[l] < pre[r]);
}
craft(s);
return 1;
}
