Codeforces Beta Round #35 (Div. 2) E. Parade(扫描线)

题目链接

只要会做，周长并，这题肯定有思路。

有个小地方敲错了，细心啊，扫描线，有一段时间没写过了，还有注意排序的问题，很重要。

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <vector>
 #include <cmath>
 #include <algorithm>
 using namespace std;
 #define LL __int64
 #define lson l,m,rt<<1
 #define rson m+1,r,rt<<1|1
 int que[];
 int sum[*];
 int cnt[*];
 int ax[],ay[];
 struct node
 {
     int h,x,c;
     node(){}
     node(int a,int b,int c):h(a),x(b),c(c){}
     bool operator < (const node &S)const
     {
         if(x == S.x)
         {
             if(c != S.c)
             return c > S.c;
             else if(c == )
             return h > S.h;
             else if(c == -)
             return h < S.h;
         }
         return x < S.x;
     }
 }mat[];
 void pushup(int rt,int l,int r)
 {
     if(cnt[rt])
     sum[rt] = que[r+] - que[l];
     else if(l == r)
     sum[rt] = ;
     else
     sum[rt] = sum[rt<<] + sum[rt<<|];
 }
 void update(int L,int R,int c,int l,int r,int rt)
 {
     int m;
     if(L <= l&&r <= R)
     {
         cnt[rt] += c;
         pushup(rt,l,r);
         return ;
     }
     m = (l + r)>>;
     if(L <= m)
     update(L,R,c,lson);
     if(R > m)
     update(L,R,c,rson);
     pushup(rt,l,r);
     return ;
 }
 int bin(int x,int y)
 {
     int str,end,mid;
     str = ;
     end = y;
     while(str <= end)
     {
         mid = (str+end)/;
         if(que[mid] == x)
         return mid;
         else if(que[mid] > x)
         end = mid - ;
         else
         str = mid + ;
     }
     return mid;
 }
 int main()
 {
     int n,i,h,l,r,num;
     freopen("input.txt","r",stdin);
     freopen("output.txt","w",stdout);
     scanf("%d",&n);
     num = ;
     for(i = ;i < n;i ++)
     {
         scanf("%d%d%d",&h,&l,&r);
         que[i] = h;
         mat[num++] = node(h,l,);
         mat[num++] = node(h,r,-);
     }
     que[n] = ;
     sort(que,que+n+);
     sort(mat,mat+num);
     int k = ;
     for(i = ;i <= n;i ++)
     {
         if(que[i] != que[i-])
         que[k++] = que[i];
     }
     int tn = ,pre = ;
     for(i = ;i < num;i ++)
     {
         l = ;
         r = bin(mat[i].h,k-) - ;
         if(l <= r)
         {
             update(l,r,mat[i].c,,k-,);
         }
         if(pre != sum[])
         {
             ax[tn] = mat[i].x;
             ay[tn++] = pre;
             ax[tn] = mat[i].x;
             ay[tn++] = sum[];
             pre = sum[];
         }
     }
     printf("%d\n",tn);
     for(i = ;i < tn;i ++)
     {
         printf("%d %d\n",ax[i],ay[i]);
     }
     return ;
 }