HUD 1542 -- Atlanta HDU

Scanning line problems

The first scanning line was followed by other people's code.

The tree does not have much content, so it is not put into the structure.

Map ing is very convenient and inefficient.

// 0 Ms 368 K g ++ # include <map> # include <iostream> # include <cstdio> # include <cstring> # include <algorithm> using namespace STD; # define maxn 205 # define mid (L + r)> 1) # define ls (RT <1) # define RS (RT <1 | 1) struct line {double L, R; double H; int flag; line () {} line (double A, double B, double C, int D): l (), R (B), H (C), flag (d) {}} A [maxn <1]; Double X [maxn <1]; // The X-axis int cover [maxn <2] from the left start point of the interval; // The number of times the entire interval is overwritten. If not, the value 0 double is assigned. Sum [maxn <2]; // The overwrite length of int CNT, K; bool CMP (const line & A, const line & B) {return. h <B. h;} void pushup (int l, int R, int RT) {If (cover [RT]) sum [RT] = x [R + 1]-X [l]; else if (L = r) sum [RT] = 0; else sum [RT] = sum [ls] + sum [RS];} void change (int c, int L, int R, int L, int R, int RT) {If (L = L & R = r) {cover [RT] + = C; pushup (L, R, RT); return;} If (r <= mid) Change (C, L, R, L, mid, ls ); else if (L> mid) Change (C, L, R, Mid + 1, R, RS); Else {change (C, L, mid, L, mid, ls); change (C, Mid + 1, R, Mid + 1, R, RS );} pushup (L, R, RT) ;}int main () {int N; double x1, x2, Y1, Y2; int c = 1; while (~ Scanf ("% d", & N), n) {CNT = 0; k = 0; Map <double, int> m; For (INT I = 0; I <n; I ++) {scanf ("% lf", & X1, & Y1, & X2, & Y2 ); A [CNT ++] = line (x1, x2, Y1, 1); A [CNT ++] = line (x1, x2, Y2,-1 ); if (M [X1] = 0) m [X1] = ++ K; If (M [X2] = 0) m [X2] = ++ K ;} map <double, int>: iterator ITER; k = 0; For (iter = m. begin (); iter! = M. end (); ITER ++) {x [++ K] = ITER-> first; ITER-> second = K;} // build (1, 1, k ); memset (sum, 0, sizeof (SUM); memset (cover, 0, sizeof (cover); sort (A, A + CNT, CMP); double ans = 0.0; for (INT I = 0; I <cnt-1; I ++) {int L = m [A [I]. l]; // refers to the interval number int r = m [A [I] starting from this point. r]-1; // The interval label on the right should be-1 Change (A [I]. flag, L, R, 1, K-1, 1); ans + = sum [1] * (a [I + 1]. h-A [I]. h);} printf ("Test Case # % d \ ntotal received area: %. 2f \ n ", C ++, ANS);} return 0 ;}