HDU 1542-Atlanta

 

Question address: http://acm.hdu.edu.cn/showproblem.php? PID = 1, 1542

 

This is my first scanned line question.

 

Method: Line Segment tree + scanning line.

 

Scan the X axis to the right of the X axis.

Sort the values of X first, and convert the values of Y to vertices.

Then scanning is performed according to the ascending order of X.

Update an interval using a line segment tree, and record the total length of all intervals in the outbound state.

Multiply the total length by the span of X to obtain an area.

Add the obtained area at a time, and the final total area is the result.

 

PS:

Wa has been in existence for a long time. I checked it for more than two hours...

At last, I found that one carriage return is missing...

When it comes to adding...

I wiped it. Why didn't we return PE but wa !!!

 

# Include <iostream> # include <cstdio> # include <algorithm> # define LL (v <1) # define RR (v <1 | 1) # define tmid (L + r)> 1) Using namespace STD; const int maxn = 201; struct node {Double X, Y1, Y2; int flag; node () {} node (double A, double B, double C, int d) {x = A, Y1 = B, y2 = C, flag = D ;} bool friend operator <(node A, Node B) {return. x <B. X ;}} P [maxn]; int rec [maxn <2]; double Len [maxn <2], F [maxn]; void Update (INT l, int R, int flag, int L, Int R, int v) {If (L <= L & R <= r) Rec [v] + = flag; else {If (L <= tmid) update (L, R, flag, L, tmid, LL); If (r> tmid) Update (L, R, flag, tmid + 1, R, RR );} if (REC [v]) Len [v] = f [R + 1]-f [l]; else if (L = r) Len [v] = 0; else Len [v] = Len [ll] + Len [RR];} int tol; int Bin (Double X) {int L, R, mid; L = 0, R = tol; while (L <= r) {mid = tmid; If (F [Mid] = x) return mid; else if (F [Mid] <X) L = Mid + 1; else r = mid-1 ;}} int main () {int I, j, T = 1, n, CNT; double X1, Y1, X2, y2, sum; whi Le (~ Scanf ("% d", & N) {If (! N) break; CNT = 0; while (n --) {scanf ("% lf", & X1, & Y1, & X2, & Y2 ); P [CNT] = node (x1, Y1, Y2, 1); F [CNT ++] = Y1; P [CNT] = node (X2, Y1, Y2, -1); F [CNT ++] = Y2;} Sort (F, F + CNT); sort (p, p + CNT); For (Tol = 0, I = 1; I <CNT; I ++) if (F [I-1]! = F [I]) f [++ tol] = f [I]; memset (REC, 0, sizeof (REC); memset (Len, 0, sizeof (LEN); sum = 0; for (I = 0; I <cnt-1; I ++) {Update (Bin (P [I]. y1), Bin (P [I]. y2)-1, P [I]. flag, 0, Tol, 1); sum + = Len [1] * (p [I + 1]. x-P [I]. x);} printf ("Test Case # % d \ n", t ++); printf ("total occupied ed area: %. 2lf \ n ", sum);} return 0 ;}