POJ 3667 Hotel 线段树 区间合并

线段树区间合并果题。

传送门：http://poj.org/problem?id=3667

#include <cstdio>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <iostream>
#include <algorithm>

const int MAXN = 50005;

struct Node {
    int x,y;
    int maxlen;
    int llen,rlen;
    int lazy;
}t[MAXN << 2];

void Push_Up(int rt) {
    //Update llen and rlen;
    t[rt].llen = t[rt<<1].llen;
    t[rt].rlen = t[rt<<1|1].rlen;
    if(t[rt<<1].llen == t[rt<<1].y - t[rt<<1].x + 1) t[rt].llen += t[rt<<1|1].llen;
    if(t[rt<<1|1].rlen == t[rt<<1|1].y - t[rt<<1|1].x + 1) t[rt].rlen += t[rt<<1].rlen;

    //Update maxlen;
    t[rt].maxlen = t[rt<<1].maxlen;
    if(t[rt<<1|1].maxlen > t[rt].maxlen) t[rt].maxlen = t[rt<<1|1].maxlen;
    if(t[rt<<1].rlen + t[rt<<1|1].llen > t[rt].maxlen) t[rt].maxlen = t[rt<<1].rlen + t[rt<<1|1].llen;
}

void Push_Down(int rt) {
    if(t[rt].lazy != -1) {
        t[rt<<1].lazy = t[rt].lazy;
        t[rt<<1|1].lazy = t[rt].lazy;
        if(t[rt].lazy == 0) {
            t[rt<<1].llen = t[rt<<1].rlen = t[rt<<1].maxlen = (t[rt<<1].y - t[rt<<1].x + 1);
            t[rt<<1|1].llen = t[rt<<1|1].rlen = t[rt<<1|1].maxlen = (t[rt<<1|1].y - t[rt<<1|1].x + 1);
        }
        else {
            t[rt<<1].llen = t[rt<<1].rlen = t[rt<<1].maxlen = 0;
            t[rt<<1|1].llen = t[rt<<1|1].rlen = t[rt<<1|1].maxlen = 0;
        }
        t[rt].lazy = -1;
    }
}

void Build(int x,int y,int rt) {
    t[rt].x = x; t[rt].y = y; t[rt].lazy = -1;
    if(x == y) {
        t[rt].maxlen = 1; t[rt].llen = 1; t[rt].rlen = 1;
        return ;
    }
    int mid = (x + y) >> 1;
    Build(x,mid,rt<<1);
    Build(mid+1,y,rt<<1|1);
    Push_Up(rt);
}

void Update(int x,int y,int rt,int l,int r,int v) {
    if(x >= l && y <= r) {
        t[rt].lazy = v;
        if(v == 0) {
            t[rt].maxlen = t[rt].llen = t[rt].rlen = (y - x + 1);
        }
        else {
            t[rt].maxlen = t[rt].llen = t[rt].rlen = 0;
        }
        return ;
    }
    Push_Down(rt);
    int mid = (x + y) >> 1;
    if(mid >= l) {
        Update(x,mid,rt<<1,l,r,v);
    }
    if(mid < r) {
        Update(mid+1,y,rt<<1|1,l,r,v);
    }
    Push_Up(rt);
}

int Query(int x,int y,int rt,int w) {
    if(x == y) {
        return x;
    }
    //printf("x : %d y : %d rt : %d maxlen : %d  w : %d\n",x,y,rt,t[rt].maxlen,w);
    Push_Down(rt);
    int mid = (x + y) >> 1;
    if(t[rt<<1].maxlen >= w) return Query(x,mid,rt<<1,w);
    if(t[rt<<1].rlen + t[rt<<1|1].llen >= w) return (t[rt<<1].y - t[rt<<1].rlen + 1);
    if(t[rt<<1|1].maxlen >= w) return Query(mid+1,y,rt<<1|1,w);
    return 0;
}

void print(int x,int y,int rt) {
    printf("x : %d y : %d maxlen : %d lazy : %d\n",x,y,t[rt].maxlen,t[rt].lazy);
    if(x == y) return ;
    int mid = (x + y) >> 1;
    print(x,mid,rt<<1);
    print(mid+1,y,rt<<1|1);
}

void Deal_with() {
    int n,m;
    while(~scanf("%d %d",&n,&m)) {
        int tempa,w,pos,len;
        Build(1,n,1);
        //print(1,n,1);
        for(int i = 1 ; i <= m ; i++) {
            scanf("%d",&tempa);
            if(tempa == 1) {
                scanf("%d",&w);
                pos = Query(1,n,1,w);
                printf("%d\n",pos);
                if(pos)
                    Update(1,n,1,pos,pos+w-1,1);
                //print(1,n,1);
            } 
            else{
                scanf("%d %d",&pos,&len);
                Update(1,n,1,pos,pos+len-1,0);
            }
        }
    }
}

int main(void) {
    //freopen("a.in","r",stdin);
    Deal_with();
    return 0;
}