HDU 3265 Posters (segment tree scan line • Rectangular frame area and)

Test instructions Some rectangular posters to some small rectangular stickers in the specified position ask the last poster covering the area

A rectangular box can be divided into 4 separate small rectangles and then the scanning line can be used to calculate the area and

#include <cstdio> #include <algorithm>using namespace std;const int N = 100005, M = N << 2;typedef long L    Ong ll;struct sline{int x, y1, y2, flag;    Sline () {}; sline (int xx, int a, int b, int f): X (XX), Y1 (a), y2 (b), flag (f) {} bool operator< (const sline &s) Cons    t{return x < s.x;    }} line[n << 3];int len[m], cnt[m];void pushup (int p, int s, int e) {if (cnt[p]) len[p] = e-s + 1;    else if (s = = e) Len[p] = 0; else len[p] = len[p << 1] + len[p << 1 | 1];} void Update (int p, int s, int e, int l, int r, int v) {if (R < L) return;//After the split rectangle has y1 = y2 case if (l <= s &AMP;&A mp        E <= R) {Cnt[p] + = V;        Pushup (P, S, e);    Return    } int mid = (s + e) >> 1;    if (l <= mid) update (P << 1, S, Mid, L, R, v);    if (R > Mid) Update (P << 1 | 1, mid + 1, E, L, R, v); Pushup (P, S, e);}    int main () {int n, m, x1, y1, x2, y2, x3, Y3, X4, Y4, F; while (scanf ("%d", &n), n) {m = 0;            for (int i = 0; i < n; ++i) {scanf ("%d%d%d%d", &x1, &y1, &x2, &y2);            scanf ("%d%d%d%d", &x3, &y3, &x4, &y4);            Divide a rectangle into 4 rectangles line[m++] = sline (x1, y1, y2, 1);            line[m++] = sline (x3, y1, Y2,-1);            line[m++] = sline (x4, y1, y2, 1);            line[m++] = sline (x2, y1, y2,-1);            line[m++] = sline (x1, y1, y3, 1);            line[m++] = sline (x2, Y1, Y3,-1);            line[m++] = sline (x1, Y4, y2, 1);        line[m++] = sline (x2, Y4, Y2,-1);        } sort (line, line + M);        ll ans = 0;            for (int i = 0; i < m; ++i) {update (1, 1, N, Line[i].y1 + 1, line[i].y2, Line[i].flag);        Ans + = ll (len[1]) * (line[i + 1].x-line[i].x);    } printf ("%lld\n", ans); } return 0;} Last modified:2015-08-14 14:29 CST

Posters

Problem descriptionted have a new house with a huge window. In this big summer, Ted decides to decorate the window with some posters to prevent the glare outside. All things that Ted can find is rectangle posters.

However, Ted is such a picky guy, a every poster he finds something ugly. So before he pastes a poster in the window, he cuts a rectangular hole on this poster to remove the ugly part. Ted is also a careless guy so, some of the pasted posters may overlap when he pastes them on the window.

Ted wants to know the total area of the windows covered by posters. Now it's your job to figure it out.

To make your job easier, we assume the window was a rectangle located in a rectangular coordinate system. The window ' s bottom-left corner are at position (0, 0) and Top-right Corner are at position (50000, 50000). The edges of the window, the edges of the posters and the edges of the holes on the posters is all parallel with the coor Dinate axes.

Inputthe input contains several test cases. For each test case, the first line contains a single integer N (0<n<=50000), representing the total number of poster S. Each of the following N lines contains 8 integers x1, y1, x2, y2, x3, Y3, X4, Y4, showing details about one poster. (x1, y1) is the coordinates of the poster ' s Bottom-left corner, and (x2, y2) are the coordinates of the poster ' s top-right Corner. (x3, Y3) is the coordinates of the hole's Bottom-left corner, while (X4, Y4) is the coordinates of the hole ' s Top-right Co Rner. It is guaranteed that 0<=xi, yi<=50000 (I=1 ... 4) and x1<=x3<x4<=x2, Y1<=y3<y4<=y2.

The input ends with a line of single zero.

Outputfor each test case, output A, and the total area of Windows covered by posters.
Sample Input

20 0 10 10 1 1 9 92 2 8 8 3 3 7 70

Sample Output

56

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HDU 3265 Posters (segment tree scan line • Rectangular frame area and)