求矩形并的周长 poj 1177 picture

#include <iostream>

#include <algorithm>

#include <cmath>

using namespace std;

struct node

{

int st, ed, m, lbd, rbd;

int sequence_line, count;

} ST[40005];

void build(int st, int ed, int v)

{

ST[v].st = st;

ST[v].ed = ed;

ST[v].lbd = ST[v].rbd = ST[v].m = 0;

ST[v].sequence_line = ST[v].count = 0;

if(ed - st > 1)

{

int mid = (st+ed)/2;

build(st, mid, 2*v+1);

build(mid, ed, 2*v+2);

}

}

inline void UpData(int v)

{

if(ST[v].count>0)

{

ST[v].m = ST[v].ed - ST[v].st;

ST[v].lbd = ST[v].rbd = 1;

ST[v].sequence_line = 1;

return ;

}

if(ST[v].ed - ST[v].st == 1)

{

ST[v].m = 0;

ST[v].lbd = ST[v].rbd = 0;

ST[v].sequence_line = 0;

}

else

{

int left = 2*v+1, right = 2*v+2;

ST[v].m = ST[left].m + ST[right].m;

ST[v].sequence_line = ST[left].sequence_line + ST[right].sequence_line - (ST[left].rbd&ST[right].lbd);

ST[v].lbd = ST[left].lbd;

ST[v].rbd = ST[right].rbd;

}

}

void insert(int st, int ed, int v)

{

if(st <= ST[v].st && ed >= ST[v].ed)

{

ST[v].count++;

UpData(v);

return ;

}

int mid = (ST[v].st + ST[v].ed)/2;

if(st < mid)insert(st, ed, 2*v+1);

if(ed > mid)insert(st, ed, 2*v+2);

UpData(v);

}

void Delete(int st, int ed, int v)

{

if(st <= ST[v].st && ed >= ST[v].ed)

{

ST[v].count--;

UpData(v);

return ;

}

int mid = (ST[v].st + ST[v].ed)/2;

if(st < mid) Delete(st, ed, 2*v+1);

if(ed > mid)Delete(st, ed, 2*v+2);

UpData(v);

}

struct line

{

int x, y1, y2;//y1 < y2

bool d;//d = true 表示线段为 矩形的左边， 反之为 右边.

}a[10003];

bool cmp(line t1, line t2)

{

return t1.x<t2.x;

}

void cal_C(int n);

int main()

{

freopen("input.txt", "r", stdin);

int n, x1, x2, y1, y2, suby, upy, i, j;

while(scanf("%d", &n) != EOF)

{

j = 0;

suby = 10000;

upy = -10000;

j = 0;

for(i = 0; i < n; i++)

{

scanf("%d%d%d%d", &x1, &y1, &x2, &y2);

a[j].x = x1; a[j].y1 = y1; a[j].y2 = y2;

a[j].d = 1;

j++;

a[j].x = x2; a[j].y1 = y1; a[j].y2 = y2;

a[j].d = 0;

j++;

if(suby > y1) suby = y1;

if(upy < y2) upy = y2;

}

sort(a, a+j, cmp);

build(suby, upy, 0);

cal_C(j);

}

return 0;

}

void cal_C(int n)

{

int i, t2, sum = 0;

t2 = 0;

a
= a[n-1];

for(i = 0; i < n; i++)

{

if(a[i].d)

insert(a[i].y1, a[i].y2, 0);

else

Delete(a[i].y1, a[i].y2, 0);

sum += ST[0].sequence_line * (a[i+1].x - a[i].x) * 2;

sum += abs(ST[0].m - t2);

t2 = ST[0].m;

}

printf("%d/n", sum);

}