#include "gift.h" #include<bits/stdc++.h> using namespace std; const int nx = 5e5+5; int l[nx], r[nx], add[nx], sub[nx]; string s; int construct(int n, int r, std::vector<int> a, std::vector<int> b, std::vector<int> x) { for(int i = 0; i < r; i++) { if(x[i] == 1) add[a[i]]++, sub[b[i]+1]++; } string cur = "B"; int sum = 0; for(int i = 0; i < n; i++) { sum += add[i]; sum -= sub[i]; if(sum == 0) { if(cur == "B") cur = "R"; else cur = "B"; } s += cur; } craft(s); return 1; }