Stone Games

主席树

Code1

#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;
const int N=1000010;
using ll=long long;
const ll MAX=1000000000ll;
int n,a[N],m;
struct node
{int l,r;ll v;
}tree[N*40];
int root[N],cnt;
void insert(int &u,int pre,int l,int r,int pos)
{u=++cnt;tree[u]=tree[pre];tree[u].v+=pos;if(l==r) return;int mid=l+r>>1;if(pos<=mid) insert(tree[u].l,tree[pre].l,l,mid,pos);elseinsert(tree[u].r,tree[pre].r,mid+1,r,pos);
}
ll query(int u,int l,int r,int L,int R)
{if(!u) return 0ll;if(L<=l&&r<=R) return tree[u].v;int mid=l+r>>1;ll v=0;if(L<=mid)   v+=query(tree[u].l,l,mid,L,R);if(R>mid)v+=query(tree[u].r,mid+1,r,L,R);return v;
}int main()
{ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);cin>>n>>m;for(int i=1;i<=n;i++) cin>>a[i];for(int i=1;i<=n;i++) insert(root[i],root[i-1],1,MAX,a[i]);ll ans=0;while(m--){int l,r;cin>>l>>r;l=(l+ans)%n+1;r=(r+ans)%n+1;if(r<l) swap(l,r);ll pre=0;while(true){ll now=query(root[r],1,MAX,1,min(MAX,pre+1))-query(root[l-1],1,MAX,1,min(MAX,pre+1));if(now==pre) break;pre=now;}ans=pre+1;cout<<ans<<'\n';}
}

Code2

赛时写的树套树分块MLE

#include<set>
#include<map>
#include<cmath>
#include<stack>
#include<queue>
#include<bitset>
#include<random>
#include<bitset>
#include<string>
#include<vector>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<unordered_map>
#include<unordered_set>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,int> pli;
typedef pair<int,int> pii;
const ll mod=1e9+7;
const int N=1000010;
int a[N],n,m;
struct node
{int l,r;ll s;
}tree[N*67];int cnt;
int root[N];
int lowbit(int x){return x&-x;}void insert(int &u,int l,int r,int pos)
{if(!u) u=++cnt;tree[u].s+=pos;if(l==r) return;int mid=l+r>>1;if(pos<=mid)insert(tree[u].l,l,mid,pos);elseinsert(tree[u].r,mid+1,r,pos);
}
ll qsum(int u,int l,int r,ll L,ll R)
{if(!u) return 0ll;if(L<=l&&r<=R) return tree[u].s;int mid=l+r>>1;ll v=0;if(L<=mid)v+=qsum(tree[u].l,l,mid,L,R);if(R>mid)v+=qsum(tree[u].r,mid+1,r,L,R);return v;
}
void update(int k,int x)
{for(;k<=n;k+=lowbit(k)) insert(root[k],1,1000000000,x);
}
ll query(int l,int r,ll L,ll R)
{ll v=0;for(;r;r-=lowbit(r)) v+=qsum(root[r],1,1000000000,L,R);for(;l;l-=lowbit(l)) v-=qsum(root[l],1,1000000000,L,R);return v;
}
int main()
{ios::sync_with_stdio(false);cin.tie();cout.tie(0);cin>>n>>m;for(int i=1;i<=n;i++) cin>>a[i];for(int i=1;i<=n;i++) update(i,a[i]);ll ans=0;while(m--){ll l,r;cin>>l>>r;l=(l+ans)%n+1;r=(r+ans)%n+1;if(l>r) swap(l,r);ll pre=0;while(1){ll s=query(l-1,r,1ll,min(pre+1ll,1000000000ll));if(s==pre) break;pre=s;}ans=pre+1ll;cout<<ans<<'\n';}return 0;
}