扫描线 + 线段树， 线段树写的有点儿退化，随便了- -。。。
1 /* 2 ID:esxgx1 3 LANG:C++ 4 PROG:hdu1542 5 */ 6 #include <cstdio> 7 #include <cstring> 8 #include <deque> 9 #include <algorithm> 10 using namespace std; 11 12 #define eps 1e-5 13 #define NN 1007 14 15 struct rt{ 16 double x, y1, y2; 17 int val; 18 }; 19 rt rr[NN << 1]; 20 double mapx[NN << 1], mapy[NN << 1]; 21 22 23 #define MAXN (NN << 1) 24 25 int cnt[MAXN * 4]; 26 double sum[MAXN * 4]; 27 28 #define recursive_def int l, int r, int i 29 #define lsi i<<1 30 #define rsi i<<1 | 1 31 #define lsn l, m, lsi 32 #define rsn m, r, rsi 33 34 #define pushup sum[i] = sum[lsi] + sum[rsi]; 35 36 void build(recursive_def) 37 { 38 cnt[i] = 0; 39 sum[i] = 0; 40 if (l == r) return; 41 int m = (l+r) >> 1; 42 build(lsn); 43 if (l != m) build(rsn); 44 } 45 46 void update(int L, int R, int val, recursive_def) 47 { 48 if (l + 1 == r) { 49 if (L <= l && r <= R) { 50 if (cnt[i] * (cnt[i] + val)<=0) 51 sum[i] += val * (mapy[r] - mapy[l]); 52 cnt[i] += val; 53 // printf("%f %f (%f) ", mapy[l], mapy[r], sum[i]); 54 } 55 return; 56 } 57 int m = (l+r) >> 1; 58 if (L <= m) update(L, R, val, lsn); 59 if (m <= R && l != m) update(L, R, val, rsn); 60 pushup 61 // printf("%f %f (%f) ", mapy[l], mapy[r], sum[i]); 62 } 63 64 int cmp1(const rt &a, const rt &b) 65 { 66 return a.x < b.x; 67 } 68 69 int main(void) 70 { 71 #ifndef ONLINE_JUDGE 72 freopen("in.txt", "r", stdin); 73 #endif 74 75 int Case = 1; 76 int n; 77 while(scanf("%d", &n), n) { 78 int ri, px, py; 79 ri = px = py = 0; 80 for(int i=0; i<n; ++i) { 81 double x1, y1, x2, y2; 82 scanf("%lf%lf%lf%lf", &x1, &y1, &x2, &y2); 83 rr[ri].x = x1, rr[ri].y1 = y1, rr[ri].y2 = y2; 84 rr[ri].val = 1; ++ri; 85 rr[ri].x = x2, rr[ri].y1 = y1, rr[ri].y2 = y2; 86 rr[ri].val = -1; ++ri; 87 mapx[px++] = x1; mapx[px++] = x2; 88 mapy[py++] = y1; mapy[py++] = y2; 89 } 90 91 sort(rr, rr + ri, cmp1); 92 sort(mapx, mapx + px); px = unique(mapx, mapx + px) - mapx; 93 sort(mapy, mapy + py); py = unique(mapy, mapy + py) - mapy; 94 int j; 95 double lx, S; 96 lx = S = 0, j = 0; 97 build(0, py - 1, 1); 98 for(int i=0; i<ri; ++i) { 99 while ((mapx[j] - rr[i].x) <= eps) ++j; 100 S += (rr[i].x - lx) * sum[1]; 101 // printf("%d %f %f ", i, sum[1], (rr[i].x - lx) * sum[1]); 102 lx = rr[i].x; 103 int y1 = lower_bound(mapy, mapy + py, rr[i].y1) - mapy; 104 int y2 = lower_bound(mapy, mapy + py, rr[i].y2) - mapy; 105 // printf("->%d %d %d ", y1, y2, rr[i].val); 106 update(y1, y2, rr[i].val, 0, py - 1, 1); 107 } 108 printf("Test case #%d Total explored area: %.2f ", Case, S); 109 ++Case; 110 } 111 return 0; 112 }
| 2014-07-28 17:39:31 | Accepted | 1542 | 0MS | 324K | 2503 B | G++ |