PKU 3667 Hotel

 维护左、右、总的连续区间长度，在 update 求总的最大长度时，写成了

tsum[r] = Max(rsum[ls]+lsum[rs], Max(lsum[r], rsum[r])); 所以一直出错。

/*
notepad++ 调用 g++ 编译

cmd /k C:\ACMSOFT\DEVC\Bin\g++.exe -g -W -Wall -o $(CURRENT_DIRECTION)\$(NAME_PART).exe $(FULL_CURRENT_PATH)

*/



# include <stdio.h>



# define ls ((r)<<1)

# define rs ((r)<<1|1)

# define mid (((x)+(y))>>1)



# define N 50005



int n, m;

char cover[N<<2];

int lsum[N<<2], rsum[N<<2], tsum[N<<2];



int Max(int x, int y)

{

    return x > y ? x : y;

}



void build(int r, int x, int y)

{

    cover[r] = -1;

    lsum[r] = rsum[r] = tsum[r] = y-x+1;

    if (x == y) return;

    build(ls, x, mid);

    build(rs, mid+1, y);

}



void update(int r, int x, int y)

{

    lsum[r] = lsum[ls], rsum[r] = rsum[rs];

    if (lsum[ls] == (mid-x+1)) lsum[r] += lsum[rs];

    if (rsum[rs] == (y-mid)) rsum[r] += rsum[ls];

    tsum[r] = Max(rsum[ls]+lsum[rs], Max(tsum[ls], tsum[rs]));

}



void pushdown(int r, int x, int y)

{

    if (cover[r] != -1)

    {

        cover[ls] = cover[rs] = cover[r];

        tsum[ls] = lsum[ls] = rsum[ls] = (cover[r] ? 0:(mid-x+1));

        tsum[rs] = lsum[rs] = rsum[rs] = (cover[r] ? 0:(y-mid));

        cover[r] = -1;

    }

}



void change(int r, int x, int y, int s, int t, int val)

{

    if (s<=x && y<=t)

    {

        cover[r] = val;

        lsum[r] = rsum[r] = tsum[r] = (val ? 0:y-x+1);

        return ;

    }

    pushdown(r, x, y);

    if  (s <= mid) change(ls, x, mid, s, t, val);

    if (mid+1<=t) change(rs, mid+1, y, s, t, val);

    update(r, x, y);

}



int query(int r, int x, int y, int w)

{

    if (x == y) return x;

    pushdown(r, x, y);

    if (tsum[ls] >= w) return query(ls, x, mid, w);

    else if (rsum[ls]+lsum[rs] >= w) return mid-rsum[ls]+1;

    else if (tsum[rs] >= w) return query(rs, mid+1, y, w);

}



void solve(void)

{

    int i, op, s,  w;

    scanf("%d%d", &n, &m);

    build(1, 1, n);

    for (i = 0; i < m; ++i)

    {

        scanf("%d", &op);

        if (op == 1)

        {

            scanf("%d", &w);

            if (tsum[1] < w) printf("0\n");

            else

            {

                s = query(1, 1, n, w);

                printf("%d\n", s);

                change(1, 1, n, s, s+w-1, 1);

            }

        }

        else

        {

            scanf("%d%d", &s, &w);

            change(1, 1, n, s, s+w-1, 0);

        }

    }

}



int main()

{

    freopen("test.in", "r", stdin);

    freopen("test.out", "w", stdout);



        solve();



    return 0;

}

 563ms。