BZOJ1857【三分法】

/* I will wait for you*/#include <cstdio>#include <cstdlib>#include <cstring>#include <cmath>#include <ctime>#include <algorithm>#include <iostream>#include <fstream>#include <vector>#include <queue>#include <deque>#include <map>#include <set>#include <string>#define make make_pair#define fi first#define se secondusing namespace std;typedef long long ll;typedef unsigned long long ull;typedef pair<int,int> pii;const int maxn = 100010;const int maxm = 1010;const int maxs = 26;const int inf = 0x3f3f3f3f;const int P = 1000000007;const double error = 1e-1;inline int read(){int x = 0, f = 1;char ch = getchar();while (ch <= 47 || ch >= 58)f = (ch == 45 ? -1 : 1), ch = getchar();while (ch >= 48 && ch <= 57)x = x * 10 + ch - 48, ch = getchar();return x * f;}struct point{double x, y;} A, B, C, D;point operator + (point a, point b){return (point) {a.x + b.x, a.y + b.y};}point operator - (point a, point b){return (point) {a.x - b.x, a.y - b.y};}point operator * (point a, double c){return (point) {a.x * c, a.y * c};}point operator / (point a, double c){return (point) {a.x / c, a.y / c};}double v1, v2, v3, ans = 1e9;double Dis(point a, point b){point c = a - b;return sqrt(c.x * c.x + c.y * c.y);}double Cal(point a){point d = (D - C) / 10000;double l = 0, r = 10000;while (r - l > error) {double mid1 = l + (r - l) / 3 * 1;double mid2 = l + (r - l) / 3 * 2;point b1 = C + d * mid1;point b2 = C + d * mid2;double dis1 = Dis(a, b1) / v3 + Dis(b1, D) / v2;double dis2 = Dis(a, b2) / v3 + Dis(b2, D) / v2;if (dis1 >= dis2)l = mid1;if (dis1 < dis2)r = mid2;}double mid = (l + r) / 2;point b = C + d * mid;return Dis(a, b) / v3 + Dis(b, D) / v2;}int main(){scanf("%lf%lf", &A.x, &A.y);scanf("%lf%lf", &B.x, &B.y);scanf("%lf%lf", &C.x, &C.y);scanf("%lf%lf", &D.x, &D.y);scanf("%lf%lf%lf", &v1, &v2, &v3);point d = (B - A) / 10000;for (int i = 0; i <= 10000; i++) {point E = A + d * i;double dis = Cal(E) + Dis(A, E) / v1;ans = min(dis, ans);}printf("%.2lf\n", ans);return 0;}

似乎是可以三分里面套三分的.

/* I will wait for you*/#include <cstdio>#include <cstdlib>#include <cstring>#include <cmath>#include <ctime>#include <algorithm>#include <iostream>#include <fstream>#include <vector>#include <queue>#include <deque>#include <map>#include <set>#include <string>#define make make_pair#define fi first#define se secondusing namespace std;typedef long long ll;typedef unsigned long long ull;typedef pair<int,int> pii;const int maxn = 100010;const int maxm = 1010;const int maxs = 26;const int inf = 0x3f3f3f3f;const int P = 1000000007;const double error = 1e-5;inline int read(){int x = 0, f = 1;char ch = getchar();while (ch <= 47 || ch >= 58)f = (ch == 45 ? -1 : 1), ch = getchar();while (ch >= 48 && ch <= 57)x = x * 10 + ch - 48, ch = getchar();return x * f;}struct point{double x, y;} A, B, C, D;point operator + (point a, point b){return (point) {a.x + b.x, a.y + b.y};}point operator - (point a, point b){return (point) {a.x - b.x, a.y - b.y};}point operator * (point a, double c){return (point) {a.x * c, a.y * c};}point operator / (point a, double c){return (point) {a.x / c, a.y / c};}double v1, v2, v3;double Dis(point a, point b){point c = a - b;return sqrt(c.x * c.x + c.y * c.y);}double Cal2(point a){point d =D - C;double l = 0, r = 1;while (r - l > error) {double mid1 = l + (r - l) / 3 * 1;double mid2 = l + (r - l) / 3 * 2;point b1 = C + d * mid1;point b2 = C + d * mid2;double dis1 = Dis(a, b1) / v3 + Dis(b1, D) / v2;double dis2 = Dis(a, b2) / v3 + Dis(b2, D) / v2;if (dis1 >= dis2)l = mid1;if (dis1 < dis2)r = mid2;}double mid = (l + r) / 2;point b = C + d * mid;return Dis(a, b) / v3 + Dis(b, D) / v2;}double Cal1(){point d = B - A;double l = 0, r = 1;while (r - l > error) {double mid1 = l + (r - l) / 3 * 1;double mid2 = l + (r - l) / 3 * 2;point a1 = A + d * mid1;point a2 = A + d * mid2;double dis1 = Dis(A, a1) / v1 + Cal2(a1);double dis2 = Dis(A, a2) / v1 + Cal2(a2);if (dis1 >= dis2)l = mid1;if (dis1 < dis2)r = mid2;}double mid = (l + r) / 2;point a = A + d * mid;return Dis(A, a) / v1 + Cal2(a);}int main(){scanf("%lf%lf", &A.x, &A.y);scanf("%lf%lf", &B.x, &B.y);scanf("%lf%lf", &C.x, &C.y);scanf("%lf%lf", &D.x, &D.y);scanf("%lf%lf%lf", &v1, &v2, &v3);printf("%.2lf\n", Cal1());return 0;}