[BZOJ1593][Usaco2008 Feb]Hotel 旅馆

#include <cstdio>
#include <algorithm>
using namespace std; 
char buf[10000000], *ptr = buf - 1;
inline int readint(){
    int n = 0;
    char ch = *++ptr;
    while(ch < ‘0‘ || ch > ‘9‘) ch = *++ptr;
    while(ch <= ‘9‘ && ch >= ‘0‘){
        n = (n << 1) + (n << 3) + ch - ‘0‘;
        ch = *++ptr;
    }
    return n;
}
const int maxn = 50000 + 10;
#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
int n, m;
int mx[maxn << 2], lx[maxn << 2], rx[maxn << 2], tag[maxn << 2];
inline void PushDown(int rt, int l, int r){
    if(tag[rt] == 1){
        mx[rt << 1] = lx[rt << 1] = rx[rt << 1] = mx[rt << 1 | 1] = lx[rt << 1 | 1] = rx[rt << 1 | 1] = 0;
        tag[rt << 1] = tag[rt << 1 | 1] = 1;
        tag[rt] = -1;
    }
    if(tag[rt] == 0){
        int mid = l + r >> 1;
        mx[rt << 1] = lx[rt << 1] = rx[rt << 1] = mid - l + 1;
        mx[rt << 1 | 1] = lx[rt << 1 | 1] = rx[rt << 1 | 1] = r - mid;
        tag[rt << 1] = tag[rt << 1 | 1] = 0;
        tag[rt] = -1;
    }
}
inline void PushUp(int rt, int l, int r){
    int mid = l + r >> 1;
    if(lx[rt << 1] == mid - l + 1) lx[rt] = lx[rt << 1] + lx[rt << 1 | 1];
    else lx[rt] = lx[rt << 1];
    if(rx[rt << 1 | 1] == r - mid) rx[rt] = rx[rt << 1 | 1] + rx[rt << 1];
    else rx[rt] = rx[rt << 1 | 1];
    mx[rt] = max(mx[rt << 1], max(mx[rt << 1 | 1], rx[rt << 1] + lx[rt << 1 | 1]));
}
inline int Query(int d){
    int rt = 1, l = 1, r = n;
    while(1){
        PushDown(rt, l, r);
        if(mx[rt] < d) return 0;
        if(lx[rt] >= d) return l;
        int mid = l + r >> 1;
        if(mx[rt << 1] >= d){
            r = mid;
            rt = rt << 1;
        }
        else if(rx[rt << 1] && rx[rt << 1] + lx[rt << 1 | 1] >= d) return mid - rx[rt << 1] + 1;
        else{
            l = mid + 1;
            rt = rt << 1 | 1;
        }
    }
}
void Change(int ql, int qr, int qw, int l, int r, int rt){
    if(ql <= l && r <= qr){
        tag[rt] = qw;
        if(qw == 0) mx[rt] = lx[rt] = rx[rt] = r - l + 1;
        else mx[rt] = lx[rt] = rx[rt] = 0;
    } 
    else{
        PushDown(rt, l, r);
        int mid = l + r >> 1;
        if(ql <= mid) Change(ql, qr, qw, lson);
        if(qr > mid) Change(ql, qr, qw, rson);
        PushUp(rt, l, r);
    }
}
int main(){
    fread(buf, sizeof(char), sizeof(buf), stdin);
    n = readint();
    m = readint();
    tag[1] = 0;
    mx[1] = lx[1] = rx[1] = n;
    for(int opt, x, y, i = 1; i <= m; i++){
        opt = readint();
        x = readint();
        if(opt == 1){
            y = Query(x);
            printf("%d\n", y);
            if(y) Change(y, y + x - 1, 1, 1, n, 1);
        }
        else{
            y = readint();
            Change(x, x + y - 1, 0, 1, n, 1);
        }
    }
    return 0;
}