UOJ # 164 [2015] Tsinghua training V (segment tree)

Topic Link

http://uoj.ac/problem/164

answer

Fairy tree line problem.
First assignment may be equivalent to lose the positive infinity plus \ (the X-\) .
Assumed that a sequence of operations position from front to back are: \ (x_1, x_2, ..., x_k \)
so we have: Current the maximum value is the suffix of the sequence and the historical maximum is the largest sub-segment of the sequence and!
Then, if the largest sub-segment and definitions addition, it becomes a single point of inquiry plus range.
Direct segment tree maintenance can be time complexity \ (O (the n-\ the n-log) \) .
(Well, in fact, seems to assign seen as positive infinity plus minus \ (x \) seems to be stuck burst long longof ......)

Code

#include<bits/stdc++.h>
#define llong long long
using namespace std;

const int N = 5e5;
void updsum(llong &x,llong y) {x = x>=y?x:y;}
struct Data
{
    llong s,ls,rs,lrs;
    Data() {}
    Data(llong x) {lrs = x; x = x<0ll?0ll:x; s = ls = rs = x;}
    Data(llong _s,llong _ls,llong _rs,llong _lrs):s(_s),ls(_ls),rs(_rs),lrs(_lrs) {}
    bool operator ==(const Data &arg) const {return s==arg.s&&ls==arg.ls&&rs==arg.rs&&lrs==arg.lrs;}
};
Data operator +(const Data &arg1,const Data &arg2)
{
    Data ret(0,0,0,0);
    ret.lrs = arg1.lrs+arg2.lrs;
    ret.ls = max(arg1.ls,arg1.lrs+arg2.ls);
    ret.rs = max(arg1.rs+arg2.lrs,arg2.rs);
    ret.s = max(max(arg1.s,arg2.s),arg1.rs+arg2.ls);
    return ret;
}
llong a[N+3];
int n,q;

struct SegmentTree
{
    Data sgt[(N<<2)+3];
    void pushdown(int u)
    {
        sgt[u<<1] = sgt[u<<1]+sgt[u];
        sgt[u<<1|1] = sgt[u<<1|1]+sgt[u];
        sgt[u] = Data(0);
    }
    void build(int u,int le,int ri,llong a[])
    {
        if(le==ri) {sgt[u] = Data(a[le]); return;}
        int mid = (le+ri)>>1;
        build(u<<1,le,mid,a); build(u<<1|1,mid+1,ri,a);
    }
    void add(int u,int le,int ri,int lb,int rb,llong x)
    {
        if(le>=lb && ri<=rb) {sgt[u] = sgt[u]+Data(x); return;}
        pushdown(u);
        int mid = (le+ri)>>1;
        if(lb<=mid) add(u<<1,le,mid,lb,rb,x);
        if(rb>mid) add(u<<1|1,mid+1,ri,lb,rb,x);
    }
    llong query(int u,int le,int ri,int pos,int typ) //1:cur 2:hist
    {
        if(le==ri) {return typ==1?sgt[u].rs:sgt[u].s;}
        pushdown(u);
        int mid = (le+ri)>>1;
        if(pos<=mid) return query(u<<1,le,mid,pos,typ);
        else return query(u<<1|1,mid+1,ri,pos,typ);
    }
} sgt;

int main()
{
    scanf("%d%d",&n,&q); llong cur = 0ll;
    for(int i=1; i<=n; i++) scanf("%lld",&a[i]),cur = max(cur,a[i]);
    sgt.build(1,1,n,a);
    while(q--)
    {
        int opt; scanf("%d",&opt);
        if(opt==1||opt==2)
        {
            int l,r; llong x; scanf("%d%d%lld",&l,&r,&x); if(opt==1) cur+=x; if(opt==2) x=-x;
            sgt.add(1,1,n,l,r,x);
        }
        else if(opt==3)
        {
            int l,r; llong x; scanf("%d%d%lld",&l,&r,&x);
            sgt.add(1,1,n,l,r,-cur); sgt.add(1,1,n,l,r,x);
        }
        else if(opt==4||opt==5)
        {
            int pos; scanf("%d",&pos);
            llong ans = sgt.query(1,1,n,pos,opt-3); printf("%lld\n",ans);
        }
    }
    return 0;
}