HDU 2871 Memory Control

线段树综合题，好题。这几天一直在搞这道题，战况甚为惨烈。新手不建议做这道题，但是学完区间合并的请一定要独立完成此题！

4种操作。

Reset：把所有的清空。

New x：找最左边的连续x的区间，找到就输出New at A，否则输出Reject New。

Free x：找到x所在区间，如果有，就清空，并且输出Free from A to B，否则输出Reject Free。

Get x：找到第x个区间，如果有，输出Get at A，否则输出Reject Get。

对于Reset操作：首先想到的是不能每次都从新建树，肯定超时，用成段更新，lazy操作就可以了。

对于New操作：就是赤果果的区间合并，和hotel一样。

然后剩下的两个操作都不好做，至少用线段树不好搞，所以加了个vector，里面放结构体，用来记录区间的起点和终点，这样对于Get操作来说，vector就可以满足它。Free操作也是一样的，可以在vector中找出x的起点终点，删掉，并且在线段树中更新该区间。但是直接找可能超时，最好二分一下。

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<algorithm>
#include<iostream>
#include<cstring>
#include<cstdio>
#include<vector>
#include<queue>
#include<cmath>
///LOOP
#define REP(i, n) for(int i = 0; i < n; i++)
#define FF(i, a, b) for(int i = a; i < b; i++)
#define FFF(i, a, b) for(int i = a; i <= b; i++)
#define FD(i, a, b) for(int i = a - 1; i >= b; i--)
#define FDD(i, a, b) for(int i = a; i >= b; i--)
///INPUT
#define RI(n) scanf("%d", &n)
#define RII(n, m) scanf("%d%d", &n, &m)
#define RIII(n, m, k) scanf("%d%d%d", &n, &m, &k)
#define RIV(n, m, k, p) scanf("%d%d%d%d", &n, &m, &k, &p)
#define RV(n, m, k, p, q) scanf("%d%d%d%d%d", &n, &m, &k, &p, &q)
#define RFI(n) scanf("%lf", &n)
#define RFII(n, m) scanf("%lf%lf", &n, &m)
#define RFIII(n, m, k) scanf("%lf%lf%lf", &n, &m, &k)
#define RFIV(n, m, k, p) scanf("%lf%lf%lf%lf", &n, &m, &k, &p)
#define RS(s) scanf("%s", s)
///OUTPUT
#define PN printf("\n")
#define PI(n) printf("%d\n", n)
#define PIS(n) printf("%d ", n)
#define PS(s) printf("%s\n", s)
#define PSS(s) printf("%s ", n)
#define PC(n) printf("Case %d: ", n)
///OTHER
#define PB(x) push_back(x)
#define CLR(a, b) memset(a, b, sizeof(a))
#define CPY(a, b) memcpy(a, b, sizeof(b))
#define display(A, n, m) {REP(i, n){REP(j, m)PIS(A[i][j]);PN;}}
#define lson l, m, rt << 1
#define rson m + 1, r, rt << 1 | 1

using namespace std;
typedef long long LL;
typedef pair<int, int> P;
const int MOD = 9901;
const int INFI = 1e9 * 2;
const LL LINFI = 1e17;
const double eps = 1e-6;
const double pi = acos(-1.0);
const int N = 55555;
const int M = 22;
const int move[8][2] = {0, 1, 0, -1, 1, 0, -1, 0, 1, 1, 1, -1, -1, 1, -1, -1};

struct mem
{
    int begin, end;
    mem(){};
    mem(int a, int b){begin = a, end = b;};
}me;
vector<mem> v;
int msum[N << 2], lsum[N << 2], rsum[N << 2], col[N << 2], n;

void build(int l, int r, int rt)
{
    msum[rt] = lsum[rt] = rsum[rt] = r - l + 1;
    col[rt] = -1;
    if(l == r)return;
    int m = (l + r) >> 1;
    build(lson);
    build(rson);
}

void pushup(int rt, int m)
{
    lsum[rt] = lsum[rt << 1];
    rsum[rt] = rsum[rt << 1 | 1];
    if(lsum[rt] == (m - (m >> 1)))lsum[rt] += lsum[rt << 1 | 1];
    if(rsum[rt] == (m >> 1))rsum[rt] += rsum[rt << 1];
    msum[rt] = max(rsum[rt << 1] + lsum[rt << 1 | 1], max(msum[rt << 1], msum[rt << 1 | 1]));
}

void pushdown(int rt, int m)
{
    if(col[rt] != -1)
    {
        col[rt << 1] = col[rt << 1 | 1] = col[rt];
        msum[rt << 1] = rsum[rt << 1] = lsum[rt << 1] = col[rt] ? 0 : (m - (m >> 1));
        msum[rt << 1 | 1] = rsum[rt << 1 | 1] = lsum[rt << 1 | 1] = col[rt] ? 0 : (m >> 1);
        col[rt] = -1;
    }
}

void update(int L, int R, int x, int l, int r, int rt)
{
    if(L <= l && r <= R)
    {
        msum[rt] = rsum[rt] = lsum[rt] = x ? 0 : (r - l + 1);
        col[rt] = x;
        return;
    }
    pushdown(rt, r - l + 1);
    int m = (l + r) >> 1;
    if(L <= m)update(L, R, x, lson);
    if(R > m)update(L, R, x, rson);
    pushup(rt, r - l + 1);
}

int query(int x, int l, int r, int rt)
{
    if(l == r)return l;
    int m = (l + r) >> 1, ans;
    pushdown(rt, r - l + 1);
    if(msum[rt << 1] >= x)ans = query(x, lson);
    else if(lsum[rt << 1 | 1] + rsum[rt << 1] >= x)ans = m - rsum[rt << 1] + 1;
    else ans = query(x, rson);
    pushup(rt, r - l + 1);
    return ans;
}

int bin(int x)
{
    if(!v.size())return 0;
    int l = 0, r = v.size() - 1, m;
    while(l <= r)
    {
        m = (l + r) >> 1;
        if(v[m].begin <= x && x <= v[m].end)return m;
        else if(v[m].end < x)l = m + 1;
        else r = m - 1;
    }
    return l;
}

void Reset()
{
    update(1, n, 0, 1, n, 1);
    v.clear();
    puts("Reset Now");
}

void New(int x)
{
    if(msum[1] < x)puts("Reject New");
    else
    {
        int p = query(x, 1, n, 1);
        update(p, p + x - 1, 1, 1, n, 1);
        int k = bin(p);
        me = mem(p, p + x - 1);
        v.insert(v.begin() + k, me);
        printf("New at %d\n", p);
    }
}

void Free(int x)
{
    int k = bin(x);
    if(k >= v.size())
    {
        puts("Reject Free");
        return;
    }
    if(v[k].begin <= x && x <= v[k].end)
    {
        printf("Free from %d to %d\n", v[k].begin, v[k].end);
        update(v[k].begin, v[k].end, 0, 1, n, 1);
        v.erase(v.begin() + k);
        return;
    }
    if(k && v[k - 1].begin <= x && x <= v[k - 1].end)
    {
        printf("Free from %d to %d\n", v[k - 1].begin, v[k - 1].end);
        update(v[k - 1].begin, v[k - 1].end, 0, 1, n, 1);
        v.erase(v.begin() + k - 1);
        return;
    }
    puts("Reject Free");
}

void Get(int x)
{
    if(x > v.size())puts("Reject Get");
    else printf("Get at %d\n", v[x - 1].begin);
}

int main()
{
    //freopen("input.txt", "r", stdin);

    int m, x;
    char op[10];
    while(RII(n, m) != EOF)
    {
        build(1, n, 1);
        v.clear();
        while(m--)
        {
            RS(op);
            if(op[0] == 'R')Reset();
            else
            {
                RI(x);
                if(op[0] == 'N')New(x);
                else if(op[0] == 'F')Free(x);
                else Get(x);
            }
        }
        puts("");
    }
    return 0;
}