poj 2892 &&hdu 1540 Tunnel Warfare

http://poj.org/problem?id=2892

  1 #include <cstdio>

  2 #include <cstring>

  3 #include <algorithm>

  4 #define maxn 51000

  5 using namespace std;

  6 

  7 int stack1[maxn],top;

  8 struct node

  9 {

 10     int l,r;

 11     int len,ren;

 12 }p[maxn*4];

 13 

 14 void up(int i)

 15 {

 16     p[i].len=p[i<<1].len; p[i].ren=p[i<<1|1].ren;

 17     if(p[i<<1].len==(p[i<<1].r-p[i<<1].l+1))

 18         p[i].len+=p[i<<1|1].len;

 19     if(p[i<<1|1].ren==(p[i<<1|1].r-p[i<<1|1].l+1))

 20         p[i].ren+=p[i<<1].ren;

 21 }

 22 void build_tree(int i,int l,int r)

 23 {

 24     p[i].l=l; p[i].r=r;

 25     if(l==r)

 26     {

 27         p[i].len=p[i].ren=1;

 28         return ;

 29     }

 30     int mid=(l+r)>>1;

 31     build_tree(i<<1,l,mid);

 32     build_tree(i<<1|1,mid+1,r);

 33     up(i);

 34 }

 35 

 36 void update(int id,int i,int oper)

 37 {

 38     if(p[i].l==p[i].r)

 39     {

 40         p[i].len=p[i].ren=oper;

 41         return;

 42     }

 43     int mid=(p[i].l+p[i].r)>>1;

 44     if(id<=mid)

 45         update(id,i<<1,oper);

 46     else

 47         update(id,i<<1|1,oper);

 48     up(i);

 49 }

 50 

 51 int search1(int id,int i)

 52 {

 53     if(p[i].l==p[i].r)

 54         return p[i].len;

 55     int mid=(p[i].l+p[i].r)>>1;

 56     if(id<=mid)

 57     {

 58         if(p[i<<1].r-p[i<<1].ren+1<=id)

 59             return p[i<<1].ren+p[i<<1|1].len;

 60         else

 61             search1(id,i<<1);

 62     }

 63     else

 64     {

 65         if(p[i<<1|1].len+p[i<<1|1].l-1>=id)

 66             return p[i<<1].ren+p[i<<1|1].len;

 67         else

 68             search1(id,i<<1|1);

 69     }

 70 }

 71 

 72 int main()

 73 {

 74     int n,q,a;

 75     while(scanf("%d%d",&n,&q)!=EOF)

 76     {

 77         build_tree(1,1,n);

 78         top=1;

 79         getchar();

 80         while(q--)

 81         {

 82             char ch;

 83             scanf("%c",&ch);

 84             if(ch=='D')

 85             {

 86                 scanf("%d",&a);

 87                 update(a,1,0);

 88                 stack1[top++]=a;

 89             }

 90             else if(ch=='Q')

 91             {

 92                 scanf("%d",&a);

 93                 printf("%d\n",search1(a,1));

 94             }

 95             else if(ch=='R')

 96             {

 97                 if(top>1)

 98                 {

 99                     update(stack1[--top],1,1);

100                 }

101             }

102             getchar();

103         }

104     }

105     return 0;

106 }

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