Poj_1151 Atlanta (line segment tree)

/* The scanning line problem of the Line Segment tree can be used as a template for such problems. I did this after I asked my senior brother...

Create a line segment tree by Y axis. */

Struct node {
Int L, R, C; // C indicates that the data is overwritten. If the value is not 0, the data is overwritten.
Double sum, Len; // Len indicates the length of the current segment, and sum indicates the valid length. Is the length of the area that can be included in the calculation.
} Node [n <2];

Struct line {
Double X; // record X coordinates
Double Y1;
Double Y2; // Y1, Y2 is used to record the two endpoints of a line segment of the parallel Y axis,
Int flag; // indicates the left side or the right side.
} L [N];

// My code:

# Include <iostream>
# Include <cstdio>
# Include <cstring>
# Include <algorithm>
# Define L (t) T <1
# Define r (t) T <1 | 1

Using namespace STD;

Const int n= 210;

Struct node {
Int L, R, C;
Double sum, Len;
} Node [n <2];

Struct line {
Double X;
Double Y1;
Double Y2;
Int flag;
} L [N];

Double Y [N];

Bool CMP (line A, line B ){
Return A. x <B. X;
}

Void creat (int t, int L, int R ){
Node [T]. L = L;
Node [T]. r = R;
Node [T]. c = 0;
Node [T]. Sum = 0;
Node [T]. Len = Y [R]-y [l];
If (L + 1 = r) return;
Int mid = (L + r)> 1;
Creat (L (t), L, mid );
Creat (r (t), mid, R );
}

Void updata_sum (INT t ){
If (node [T]. c> 0) node [T]. Sum = node [T]. Len;
Else if (node [T]. R! = Node [T]. L + 1) node [T]. Sum = node [L (t)]. Sum + node [r (t)]. sum;
Else node [T]. Sum = 0;
}

Void updata (int t, int L, int R, int c ){
If (node [T]. L = L & node [T]. r = r ){
If (c) node [T]. c ++;
Else node [T]. c --;
Updata_sum (t );
Return;
}
Int mid = (node [T]. L + node [T]. R)> 1;
If (L> = mid) updata (r (t), L, R, C );
Else if (r <= mid) updata (L (t), L, R, C );
Else {
Updata (L (t), L, mid, C );
Updata (r (t), mid, R, C );
}
Updata_sum (t );
}

Int find (double key, int N ){
Int L = 1, R = N, mid;
While (L <= r ){
Mid = (L + r)> 1;
If (Y [Mid] = Key) return mid;
Else if (Y [Mid]> key) r = mid-1;
Else l = Mid + 1;
}
Return 0;
}

Int main (){
// Freopen ("data. In", "r", stdin );

Int t, n, m, I, CAS = 0;
Double x1, x2, Y1, Y2, ans;
While (scanf ("% d", & T), t ){
M = 1;
While (t --){
Scanf ("% lf", & X1, & Y1, & X2, & Y2 );
Y [m] = Y1; L [M]. X = x1; L [M]. y1 = Y1; L [M]. y2 = Y2; L [M]. flag = 1; m ++;
Y [m] = Y2; L [M]. X = x2; L [M]. y1 = Y1; L [M]. y2 = Y2; L [M]. flag = 0; m ++;
}
Sort (Y + 1, Y + M );
Sort (L + 1, L + M, CMP );
M --; n = 2;
For (I = 1; I <m; I ++)
If (Y [I]! = Y [I + 1]) y [n ++] = Y [I + 1];
N --; creat (1, 1, n );
For (ANS = 0, I = 1; I <m; I ++ ){
If (L [I]. Flag) updata (1, find (L [I]. Y1, n), find (L [I]. Y2, n), 1 );
Else updata (1, find (L [I]. Y1, n), find (L [I]. Y2, n), 0 );
Ans + = node [1]. Sum * (L [I + 1]. X-L [I]. X );
}
Printf ("Test Case # % d \ ntotal received area: %. 2lf \ n", ++ cas, ANS );
}
Return 0;
}