【HDU】1540 Tunnel Warfare 
  1 #include<cstdio>
  2 #include<stack>
  3 #define MAXN 50010
  4 #define MAX(a,b) ((a)>(b)?(a):(b))
  5 using namespace std;
  6 stack<int>st;
  7 struct node
  8 {
  9     int left,right;
 10 };
 11 node tree[MAXN<<2];
 12 void Build(int L,int R,int rt)
 13 {
 14     tree[rt].left=tree[rt].right=R-L+1;
 15     if(L!=R)
 16     {
 17         int mid=(L+R)>>1;
 18         Build(L,mid,rt<<1);
 19         Build(mid+1,R,rt<<1|1);
 20     }
 21 }
 22 inline void PushUp(int mid,int L,int R,int rt)
 23 {
 24     tree[rt].left=tree[rt<<1].left;
 25     tree[rt].right=tree[rt<<1|1].right;
 26     if(tree[rt].left==mid-L+1)
 27         tree[rt].left+=tree[rt<<1|1].left;
 28     if(tree[rt].right==R-mid)
 29         tree[rt].right+=tree[rt<<1].right;
 30 }
 31 void Update(int x,int val,int L,int R,int rt)
 32 {
 33     if(L==R)
 34         tree[rt].left=tree[rt].right=val;
 35     else
 36     {
 37         int mid=(L+R)>>1;
 38         if(x<=mid)
 39             Update(x,val,L,mid,rt<<1);
 40         else
 41             Update(x,val,mid+1,R,rt<<1|1);
 42         PushUp(mid,L,R,rt);
 43     }
 44 }
 45 int Query(int x,int L,int R,int rt)
 46 {
 47     if(L==R)
 48         return tree[rt].left;
 49     int mid=(L+R)>>1;
 50     if(x<=mid)
 51     {
 52         if(tree[rt<<1].left==mid-L+1)
 53             return tree[rt<<1].left+tree[rt<<1|1].left;
 54         else if(L+tree[rt<<1].left>x)
 55             return tree[rt<<1].left;
 56         else if(x>mid-tree[rt<<1].right)
 57             return tree[rt<<1].right+tree[rt<<1|1].left;
 58         else
 59             return Query(x,L,mid,rt<<1);
 60     }
 61     else
 62     {
 63         if(tree[rt<<1|1].right==R-mid)
 64             return tree[rt<<1|1].right+tree[rt<<1].right;
 65         else if(x<mid+1+tree[rt<<1|1].left)
 66             return tree[rt<<1].right+tree[rt<<1|1].left;
 67         else if(x>R-tree[rt<<1|1].right)
 68             return tree[rt<<1|1].right;
 69         else
 70             return Query(x,mid+1,R,rt<<1|1);
 71     }
 72 }
 73 int main()
 74 {
 75     int n,m,x;
 76     char ch;
 77     while(~scanf("%d%d",&n,&m))
 78     {
 79         Build(1,n,1);
 80         for(;!st.empty();st.pop());
 81         while(m--)
 82         {
 83             scanf(" %c",&ch);
 84             if(ch=='D')
 85             {
 86                 scanf("%d",&x);
 87                 st.push(x);
 88                 Update(x,0,1,n,1);
 89             }
 90             else if(ch=='Q')
 91             {
 92                 scanf("%d",&x);
 93                 printf("%d\n",Query(x,1,n,1));
 94             }
 95             else
 96             {
 97                 if(!st.empty())
 98                 {
 99                     Update(st.top(),1,1,n,1);
100                     st.pop();
101                 }
102             }
103         }
104     }
105     return 0;
106 }
posted on 2012-05-23 11:45  DrunBee  阅读(407)  评论(0)  编辑  收藏  举报