#include "gift.h" using namespace std; int construct(int n, int r, std::vector<int> a, std::vector<int> b, std::vector<int> x) { std::string s(n, 'R'); vector<int> vc1(n,-1); vector<int> vc2(n,-1); for(int i = 0;i < r;i++){ if(x[i] == 1) vc1[a[i]] = b[i]; else vc2[a[i]] = b[i]; } int cur = 0; for(int i = 0;i < n;i++){ if(i > cur){ if(s[i-1] == 'R') s[i] = 'B'; else s[i] = 'R'; } else if(i > 0){ s[i] = s[i-1]; } if(vc1[i] != -1){ cur = max(cur,vc1[i]); } } cur = 1e9; for(int i = 0;i < n;i++){ if(vc2[i] != -1){ cur = min(cur,vc2[i]); } if(i > 0 && s[i-1] != s[i]) cur = 1e9; if(i >= cur) return 0; } craft(s); return 1; }