Perimeter of multiple rectangular Edges

The world is still so impermanence, the key is to have a normal heart!

Http://www.cnblogs.com/Booble/archive/2010/10/10/1847163.html

For a detailed and patient explanation, you can understand it at a glance, and you will be fined 10 for false positives!

The code and comments for poj1177 to calculate the perimeter of multiple rectangular edges are as follows:

Tucao: Wa has been around for a long time. Why? Maxn is too small.

People's coordinates are [-]. Even if they are discretization, there should be many points.

 

Where I am prone to errors:

R> M: recursive right subtree

Maxn

Discretization
The START pointer is 1.

// Attention: // regards a line segment tree as a line segment, the significance of each vertex is to include a line segment whose unit is backward # include <iostream> # include <cstdio> # include <cstring> # include <algorithm> # include <cmath> # define lson l, m, RT <1 # define rson m + 1, R, RT <1 | 1 # define maxn 22222 using namespace STD; // indicates whether the right endpoint of the Line Segment indicated by the Left endpoint and right endpoint of the range is overwritten by bool LBD [maxn <2], RBD [maxn <2]; int Len [maxn <2]; // indicates the length covered by the node range. Int CNT [maxn <2], numseg [maxn <2]; // represents the number of lines covered by this interval, and the number of lines s from a distance. Truct seg {int L, R, H, s; seg () {} seg (int A, int B, int C, int D): l (), R (B), H (C), S (d) {} bool operator <(const seg & CMP) const {If (H = CMP. h) Return S> CMP. s; return H <CMP. h ;}} seg [maxn <1]; void push_up (int rt, int L, int R) {If (CNT [RT]) {LBD [RT] = RBD [RT] = true; Len [RT] = r-L + 1; numseg [RT] = 2;} else if (L = r) {Len [RT] = numseg [RT] = LBD [RT] = RBD [RT] = 0;} else {LBD [RT] = LBD [RT <1]; RBD [RT] = RBD [RT <1 | 1]; len [RT] = Len [RT <1] + Len [RT <1 | 1]; numseg [RT] = numseg [RT <1] + numseg [RT <1 | 1]; if (LBD [RT <1 | 1] & RBD [RT <1]) numseg [RT]-= 2 ;}} void Update (int l, int R, int C, int L, int R, int RT) {If (L <= L & R <= r) {CNT [RT] + = C; push_up (RT, l, R); return;} int M = (L + r)> 1; if (L <= m) Update (L, R, C, lson ); if (r> m) Update (L, R, C, rson); push_up (RT, L, R) ;}int main () {int n, a, B, c, d, s; int ret; while (scanf ("% d", & N )! = EOF) {S = 0; ret = 0; int lT = 1000000, rT =-100000; memset (Len, 0, sizeof (LEN); memset (numseg, 0, sizeof (numseg); memset (CNT, 0, sizeof (CNT); memset (LBD, 0, sizeof (LBD); memset (RBD, 0, sizeof (RBD); For (INT I = 0; I <n; I ++) {scanf ("% d", &, & B, & C, & D); Lt = min (LT, a); RT = max (RT, C ); // 1 indicates the bottom of the rectangle seg [s ++] = seg (A, C, B, 1); //-1 indicates the top of the rectangle. // I scanned the image from the bottom up, So I inserted the image below, delete the above Code // The CNT [RT] + = C in the update statement returns seg [s ++] = seg (a, c, d,-1 );} sort (SEG, SEG + S); // sorting ensures that int last = 0 is scanned from bottom up; seg [s]. H = 0; For (INT I = 0; I <s; I ++) {If (SEG [I]. L <seg [I]. r) // just because of the definition of the Line Segment tree, R-1 update (SEG [I] is inserted here. l, SEG [I]. r-1, SEG [I]. s, LT, RT, 1); RET + = ABS (LEN [1]-last ); // difference RET + = numseg [1] * (SEG [I + 1]. h-seg [I]. h); // Number of line segments * length of the statistical interval last = Len [1];} printf ("% d \ n", RET);} return 0 ;} int Bin (INT low, int high, double key, double X []) {While (low