POJ 3667 Hotel 线段树 区间合并

结点记录三个信息，区间最长的连续空房间，最长前缀和后缀

//#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<iostream>
#include<sstream>
#include<cmath>
#include<climits>
#include<string>
#include<map>
#include<queue>
#include<vector>
#include<stack>
#include<set>
using namespace std;
typedef long long ll;
typedef pair<int,int> pii;
#define pb(a) push_back(a)
#define INF 0x1f1f1f1f
#define lson idx<<1,l,mid
#define rson idx<<1|1,mid+1,r
#define PI  3.1415926535898
template<class T> T min(const T& a,const T& b,const T& c) {
    return min(min(a,b),min(a,c));
}
template<class T> T max(const T& a,const T& b,const T& c) {
    return max(max(a,b),max(a,c));
}
void debug() {
#ifdef ONLINE_JUDGE
#else

    freopen("d:\in.txt","r",stdin);
    freopen("d:\out1.txt","w",stdout);
#endif
}
int getch() {
    int ch;
    while((ch=getchar())!=EOF) {
        if(ch!=' '&&ch!=' ')return ch;
    }
    return EOF;
}
const int MAXN=55000;
struct node{
    int maxv,pre,suf;
};
node tree[MAXN<<2];
int setv[MAXN<<2];
int PushDown(int idx,int l,int r) {
    if(setv[idx]!=-1) {
        int mid=(r+l)>>1;
        setv[idx<<1]=setv[idx<<1|1]=setv[idx];
        tree[idx<<1].maxv=tree[idx<<1].pre=tree[idx<<1].suf=setv[idx]*(mid-l+1);
        tree[idx<<1|1].maxv=tree[idx<<1|1].pre=tree[idx<<1|1].suf=setv[idx]*(r-mid);
        setv[idx]=-1;
    }
    return 0;
}
int PushUp(int idx,int l,int r) {
    int mid=(r+l)>>1;
    int ls=idx<<1,rs=idx<<1|1;
    tree[idx].maxv=max(tree[ls].maxv,tree[rs].maxv,tree[ls].suf+tree[rs].pre);
    tree[idx].pre=tree[ls].pre==mid-l+1?tree[ls].pre+tree[rs].pre:tree[ls].pre;
    tree[idx].suf=tree[rs].suf==r-mid?tree[rs].suf+tree[ls].suf:tree[rs].suf;
    return 0;
}
int build(int idx,int l,int r) {
    setv[idx]=-1;
    tree[idx].maxv=tree[idx].pre=tree[idx].suf=r-l+1;
    if(l==r)return 0;
    int mid=(r+l)>>1;
    build(lson);
    build(rson);
    return 0;
}
int update(int idx,int l,int r,int tl,int tr ,int v) {
    if(tl<=l&&tr>=r)
    {
        setv[idx]=v;
        tree[idx].maxv=tree[idx].pre=tree[idx].suf=v*(r-l+1);
        return 0;
    }
    PushDown(idx,l,r);
    int mid=(r+l)>>1;
    if(tl<=mid)update(lson,tl,tr,v);
    if(tr>mid)update(rson,tl,tr,v);
    PushUp(idx,l,r);
    return 0;
}
int query(int idx,int l,int r,int v){
    if(r-l+1==v)return l;
    PushDown(idx,l,r);
    int mid=(r+l)>>1;
    if(tree[idx<<1].maxv>=v)return query(lson,v);
    else if(tree[idx<<1].suf!=0&&tree[idx<<1].suf+tree[idx<<1|1].pre>=v)return mid-tree[idx<<1].suf+1;
    else return query(rson,v);
}
int main(){
    int n,m;
    while(scanf("%d%d",&n,&m)!=EOF) {
        build(1,1,n);
        for(int q=1;q<=m;q++) {
            int op;
            scanf("%d",&op);
            if(op==1){
                int v;
                scanf("%d",&v);
                if(tree[1].maxv<v)
                    printf("0
");
                else {
                    int pos=query(1,1,n,v);
                    printf("%d
",pos);
                    update(1,1,n,pos,pos+v-1,0);
                }
            }else {
                int a,b;
                scanf("%d%d",&a,&b);b=a+b-1;
                update(1,1,n,a,b,1);
            }
        }
    }
    return 0;
}