POJ 3277 City Horizon(扫描线+线段树)

题目链接

类似求面积并。。2Y。。

 #include <cstdio>
 #include <cstring>
 #include <string>
 #include <cmath>
 #include <algorithm>
 using namespace std;
 #define LL __int64
 #define maxn 40100
 #define lson l , m, rt<<1
 #define rson m+1, r,rt<<1|1
 int que[maxn*];
 int sum[maxn*];
 int cnt[maxn*];
 struct node
 {
     int x,y,s;
     node(){}
     node(int a,int b,int c):x(a),y(b),s(c){}
     bool operator < (const node &S)const
     {
         return x < S.x;
     }
 }mat[maxn*];
 int bin(int x,int n)
 {
     int str,mid,end;
     str = ;
     end = n;
     while(str <= end)
     {
         mid = (str+end)/;
         if(que[mid] == x)
         return mid;
         else if(que[mid] > x)
         end = mid - ;
         else
         str = mid + ;
     }
     return mid;
 }
 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);
 }
 int main()
 {
     int n,a,b,c,i,k,num,l,r;
     while(scanf("%d",&n)!=EOF)
     {
         memset(cnt,,sizeof(cnt));
         memset(sum,,sizeof(sum));
         num = ;
         for(i = ;i < n;i ++)
         {
             scanf("%d%d%d",&a,&b,&c);
             que[num] = ;
             mat[num++] = node(a,c,);
             que[num] = c;
             mat[num++] = node(b,c,-);
         }
         sort(mat,mat+num);
         sort(que,que+num);
         k = ;
         for(i = ;i < num;i ++)
         {
             if(que[k] != que[i])
             que[k++] = que[i];
         }
         LL ans = ;
         for(i = ;i < num-;i ++)
         {
             l = ;
             r = bin(mat[i].y,k-)-;
             if(l <= r)
             update(l,r,mat[i].s,,k-,);
             ans = ans + (LL)sum[]*(mat[i+].x - mat[i].x);
         }
         printf("%I64d\n",ans);
     }
     return ;
 }