题目链接:http://codeforces.com/contest/981/problem/E
线段树维护每个询问,然后统计每个区间中出现了多少个点,一边下放标记一边做01背包即可,当然,一看数据是1e4就知道这题不简单,bitset了解一下
代码:
#include<bits/stdc++.h> #define pb push_back using namespace std; const int MAXN=1e4+5; typedef bitset<MAXN> state; struct seg { #define lson l,mid,rt<<1 #define rson mid+1,r,rt<<1|1 vector<int> E[MAXN<<2]; void update(int L,int R,int val,int l,int r,int rt) { if(L<=l&&r<=R) { E[rt].pb(val); return ; } int mid=(l+r)>>1; if(L<=mid) update(L,R,val,lson); if(mid<R) update(L,R,val,rson); } }se; state book[MAXN<<2],cur,ans; void dfs(int l,int r,int now) { book[now]=cur; for(auto i:se.E[now]) cur|=(cur<<i); ans|=cur; if(l==r) return ; int mid=(l+r)>>1; dfs(l,mid,now<<1);dfs(mid+1,r,now<<1|1); cur=book[now]; } vector<int> res; int main() { //freopen("in.txt","r",stdin); //freopen("out.txt","w",stdout); int n,q; scanf("%d%d",&n,&q); for(int i=1;i<=q;i++) { int l,r,x; scanf("%d%d%d",&l,&r,&x); se.update(l,r,x,1,n,1); } cur=1; dfs(1,n,1); for(int i=1;i<=n;i++) if(ans[i]) res.pb(i); printf("%d\n",int(res.size())); for(auto i:res) printf("%d ",i); printf("\n"); return 0; }