hdu1540-Tunnel Warfare （线段树区间合并）

  1 #include <set>
  2 #include <map>
  3 #include <cmath>
  4 #include <ctime>
  5 #include <queue>
  6 #include <stack>
  7 #include <cctype>
  8 #include <cstdio>
  9 #include <string>
 10 #include <vector>
 11 #include <cstdlib>
 12 #include <cstring>
 13 #include <iostream>
 14 #include <algorithm>
 15 using namespace std;
 16 typedef unsigned long long ull;
 17 typedef long long ll;
 18 const int inf = 0x3f3f3f3f;
 19 const double eps = 1e-8;
 20 const int maxn = 5e4+10;
 21 int ls[maxn<<2],ms[maxn<<2],rs[maxn<<2];
 22 stack<int>S;
 23 void build(int l,int r,int pos)
 24 {
 25     ls[pos] = rs[pos] = ms[pos] = r - l + 1;
 26     if (l == r)
 27         return;
 28     int mid = (l + r) >> 1;
 29     build(l,mid,pos<<1);
 30     build(mid+1,r,pos<<1|1);
 31 }
 32 void update(int l,int r,int pos,int x,int val)
 33 {
 34     if (l == r)
 35     {
 36         ls[pos] = rs[pos] = ms[pos] = val;
 37         return;
 38     }
 39     int mid = (l + r) >> 1;
 40     if (x <= mid)
 41         update(l,mid,pos<<1,x,val);
 42     if (x > mid)
 43         update(mid+1,r,pos<<1|1,x,val);
 44     ms[pos] = max(rs[pos<<1]+ls[pos<<1|1],max(ms[pos<<1],ms[pos<<1|1]));
 45     ls[pos] = ls[pos<<1];
 46     rs[pos] = rs[pos<<1|1];
 47     if (mid-l+1==rs[pos<<1])  
 48         ls[pos] += ls[pos<<1|1];
 49     if (r-mid==ls[pos<<1|1])
 50         rs[pos] += rs[pos<<1];
 51 }
 52 int query(int l,int r,int pos,int x)
 53 {
 54     if (ms[pos] == r - l + 1 || !ms[pos] || l == r)
 55     {
 56         return ms[pos];
 57     }
 58     int mid = (l + r) >> 1;
 59     if (x <= mid)
 60     {
 61         if (x >= mid - rs[pos<<1] + 1)
 62             return query(l,mid,pos<<1,x) + query(mid+1,r,pos<<1|1,mid+1);
 63         else
 64             return query(l,mid,pos<<1,x);
 65     }
 66     else
 67     {
 68         if (x <= mid+ls[pos<<1|1])
 69             return query(mid+1,r,pos<<1|1,x) + query(l,mid,pos<<1,mid);
 70         else
 71             return query(mid+1,r,pos<<1|1,x);
 72     }
 73 }
 74 int main(void)
 75 {
 76     #ifndef ONLINE_JUDGE
 77         freopen("in.txt","r",stdin);
 78     #endif
 79     int n,m;
 80     while (~scanf ("%d%d",&n,&m))
 81     {
 82         build(1,n,1);
 83         char op[10];
 84         for (int i = 0; i < m; i++)
 85         {
 86             int x;
 87             scanf ("%s",op);
 88             if (op[0] == ‘D‘)
 89             {
 90                 scanf ("%d",&x);
 91                 update(1,n,1,x,0);
 92                 S.push(x);
 93             }
 94             if (op[0] == ‘Q‘)
 95             {
 96                 scanf ("%d",&x);
 97                 printf("%d\n",query(1,n,1,x));
 98             }
 99             if (op[0] == ‘R‘)
100             {
101                 if (!S.empty())
102                 {
103                     int tmp = S.top();
104                     S.pop();
105                     update(1,n,1,tmp,1);
106                 }
107             }
108         }
109         while (!S.empty())
110             S.pop();
111     }
112     return 0;
113 }