HDOJ 2871 Memory Control（线段树区间合并与查询）
思路：
hotel的加强版。把申请到的内存都放到vector容器里面，然后再利用STL里面的upper_bound函数操作即可。写完之后感觉很爽。
#include <cstdio>
#include <algorithm>
#include <vector>
using namespace std;
#define lhs l, m, rt << 1
#define rhs m + 1, r, rt << 1 | 1
const int maxn = 50010;
int sum[maxn << 2], lsum[maxn << 2], rsum[maxn << 2];
int lab[maxn << 2];
enum __op { __free = 0, __new };
typedef struct _node {
int beg, end;
_node(int _b, int _e) : beg(_b), end(_e) { };
friend bool operator < (const _node& n1, const _node& n2) { return n1.beg < n2.beg; };
} node ;
void PushUp(int l, int r, int rt)
{
lsum[rt] = lsum[rt << 1];
rsum[rt] = rsum[rt << 1 | 1];
int m = (l + r) >> 1;
if (lsum[rt] == m - l + 1)
lsum[rt] += lsum[rt << 1 | 1];
if (rsum[rt] == r - m)
rsum[rt] += rsum[rt << 1];
sum[rt] = max(sum[rt << 1], sum[rt << 1 | 1]);
sum[rt] = max(rsum[rt << 1] + lsum[rt << 1 | 1], sum[rt]);
}
void PushDown(int l, int r, int rt)
{
if (lab[rt] != -1)
{
int m = (l + r) >> 1;
lab[rt << 1] = lab[rt << 1 | 1] = lab[rt];
sum[rt << 1] = lsum[rt << 1] = rsum[rt << 1] = lab[rt] ? 0 : m - l + 1;
sum[rt << 1 | 1] = lsum[rt << 1 | 1] = rsum[rt << 1 | 1] = lab[rt] ? 0 : r - m;
lab[rt] = -1;
}
}
int Query(int size, int l, int r, int rt)
{
if (l == r)
return r;
int m = (l + r) >> 1;
PushDown(l, r, rt);
if (sum[rt << 1] >= size)
return Query(size, lhs);
else if (rsum[rt << 1] + lsum[rt << 1 | 1] >= size)
return m - rsum[rt << 1] + 1;
else
return Query(size, rhs);
// PushUp(l, r, rt);
}
void Update(int beg, int end, __op op, int l, int r, int rt)
{
if (beg <= l && r <= end)
{
sum[rt] = lsum[rt] = rsum[rt] = op ? 0 : r - l + 1;
lab[rt] = op;
return ;
}
PushDown(l, r, rt);
int m = (l + r) >> 1;
if (beg <= m)
Update(beg, end, op, lhs);
if (end > m)
Update(beg, end, op, rhs);
PushUp(l, r, rt);
}
void Build(int l, int r, int rt)
{
sum[rt] = r - l + 1;
lsum[rt] = rsum[rt] = r - l + 1;
lab[rt] = -1;
if (l == r)
return ;
int m = (l + r) >> 1;
Build(lhs), Build(rhs);
}
int main()
{
int n, m;
vector<node> mblk;
while (~scanf("%d %d", &n, &m))
{
Build(1, n, 1);
mblk.clear();
for (int i = 0; i < m; ++i)
{
char op[16];
scanf("%s", op);
if (op[0] == 'N')
{
int x;
scanf("%d", &x);
if (sum[1] >= x)
{
int p = Query(x, 1, n, 1);
vector<node>::iterator iter;
Update(p, p + x - 1, __new, 1, n, 1);
printf("New at %d\n", p);
iter = upper_bound(mblk.begin(), mblk.end(), node(p, p + x - 1));
mblk.insert(iter, node(p, p + x - 1));
}
else
printf("Reject New\n");
}
else if (op[0] == 'F')
{
int x;
scanf("%d", &x);
int p = upper_bound(mblk.begin(), mblk.end(), node(x, x)) - mblk.begin() - 1;
if (p == -1 || mblk[p].end < x)
printf("Reject Free\n");
else
{
printf("Free from %d to %d\n", mblk[p].beg, mblk[p].end);
Update(mblk[p].beg, mblk[p].end, __free, 1, n, 1);
mblk.erase(mblk.begin() + p);
}
}
else if (op[0] == 'G')
{
int x;
scanf("%d", &x);
if (x <= mblk.size())
printf("Get at %d\n", mblk[x-1].beg);
else
printf("Reject Get\n");
}
else if (op[0] == 'R')
{
Update(1, n, __free, 1, n, 1);
// Build(1, n, 1);
mblk.clear();
printf("Reset Now\n");
}
}
printf("\n");
}
return 0;
}