裸裸的题目
但是按之前的搞法 重叠的边（cnt >= 2）在线段树里面有没有更新到子树
所以在线段树更新里面重了两个update
时间复杂度退化了 时间有点慢
太菜了。。。
1 #include <bits/stdc++.h> 2 #include <string.h> 3 #include <iostream> 4 #include <stdio.h> 5 #define pb push_back 6 #define fi first 7 #define se second 8 #define lson(r) (r<<1) 9 #define rson(r) ((r<<1)|1) 10 11 using namespace std; 12 13 typedef long long ll; 14 15 const int MAXN = 2e3+7; 16 const int MAXV = 507; 17 const int MAXE = 507; 18 19 struct Seg 20 { 21 int cnt; 22 double len; 23 }seg[MAXN << 2]; 24 struct Line 25 { 26 double px1, px2, h; 27 int x1, x2, flag; 28 Line() {} 29 Line(double px1, double px2, double h, int flag) : px1(px1), px2(px2), h(h), flag(flag) {} 30 bool operator < (Line l) const 31 { 32 return h < l.h; 33 } 34 }line[MAXN]; 35 double hor[MAXN]; 36 int n; 37 38 void push_up(int root, int l, int r) 39 { 40 if (seg[root].cnt >= 2) seg[root].len = hor[r+1] - hor[l]; 41 else if (l == r) seg[root].len = 0; 42 else seg[root].len = seg[lson(root)].len + seg[rson(root)].len; 43 } 44 void update(int root, int l, int r, int ul, int ur, int addval) 45 { 46 if (l > ur || r < ul) return ; 47 if (l >= ul && r <= ur) 48 { 49 seg[root].cnt += addval; 50 //cout << l << " " << r << " " << seg[root].cnt << endl; 51 int mid = (l+r) >> 1; 52 if (l == r) 53 { 54 push_up(root, l, r); 55 return ; 56 } 57 //在区间内也更新 58 update(lson(root), l, mid, ul, ur, addval); 59 update(rson(root), mid+1, r, ul, ur, addval); 60 push_up(root, l, r); 61 return; 62 } 63 int mid = (l+r) >> 1; 64 update(lson(root), l, mid, ul, ur, addval); 65 update(rson(root), mid+1, r, ul, ur, addval); 66 push_up(root, l, r); 67 } 68 double query() 69 { 70 return seg[1].len; 71 } 72 int main() 73 { 74 //freopen("in.txt", "r", stdin); 75 int T; 76 scanf("%d", &T); 77 while (T--) 78 { 79 scanf("%d", &n); 80 int num = 0; 81 memset(line, 0, sizeof(line)); 82 memset(hor, 0, sizeof(hor)); 83 memset(seg, 0, sizeof(seg)); 84 for (int i = 0; i < n; i++) 85 { 86 double x1, x2, y1, y2; 87 scanf("%lf%lf%lf%lf", &x1, &y1, &x2, &y2); 88 hor[num] = x1; 89 line[num++] = Line(x1, x2, y1, 1); 90 hor[num] = x2; 91 line[num++] = Line(x1, x2, y2, -1); 92 } 93 sort(line, line+num); 94 sort(hor, hor+num); 95 int m = unique(hor, hor+num) - hor; 96 for (int i = 0; i < num; i++) 97 { 98 line[i].x1 = lower_bound(hor, hor+m, line[i].px1) - hor; 99 line[i].x2 = lower_bound(hor, hor+m, line[i].px2) - hor; 100 } 101 double ans = 0, prey = -1; 102 for (int i = 0; i < num; i++) 103 { 104 if (prey == -1) 105 { 106 prey = line[i].h; 107 update(1, 0, m-2, line[i].x1, line[i].x2-1, line[i].flag); 108 //cout << line[i]. 109 //x1 << " " << line[i].x2 << endl; 110 continue; 111 } 112 double det = line[i].h - prey; 113 double len = query(); 114 ans += len * det; 115 prey = line[i].h; 116 //cout << line[i].x1 << " " << line[i].x2 << endl; 117 update(1, 0, m-2, line[i].x1, line[i].x2-1, line[i].flag); 118 //return 0; 119 } 120 printf("%.2f ", ans); 121 } 122 return 0; 123 }