注意两边一角,并接角的对边确定时(即用正弦定理求解时,可能会有多解的情况)
#include <cstdio> #include <cstring> #include <cmath> #include <algorithm> using namespace std; const double pi = 4 * atan(1); const double eps = 1e-4; double A[6]; void CornerToCorner () { double t = 0; for (int i = 1; i < 6; i += 2) { if (A[i] < 0) continue; t += A[i]; } for (int i = 1; i < 6; i += 2) if (A[i] < 0) A[i] = pi - t; } double getAngle(double a, double b, double c) { return acos( (a * a + b * b - c * c) / (2 * a * b) ); } void EdgeToCorner () { for (int i = 1; i < 6; i += 2) { if (A[i] < 0) A[i] = getAngle( A[(i+1)%6], A[(i+3)%6], A[i-1]); } } double getEdge(double x, double y, double c) { //printf("%lf %lf\n", c, cos(c)); return sqrt(x * x + y * y - 2 * x * y * cos(c)); } bool judge () { for (int i = 0; i < 6; i++) if (A[i] < 0) return false; if (fabs(A[1] + A[3] + A[5] - pi) > eps) { return false; } if (A[0] + A[2] <= A[4] || A[2] + A[4] <= A[0] || A[0] + A[4] <= A[2]) { return false; } /* for (int i = 0; i < 6; i += 2) printf("%lf\n", A[i] / sin(A[i+1])); */ for (int i = 0; i < 4; i += 2) { //if (fabs(A[i] / sin(A[i+1]) - A[i+2] / sin(A[i+3])) > eps) //printf("%lf\n", fabs(A[i] * sin(A[i+3]) - sin(A[i+1]) * A[i+2])); if (fabs(A[i] * sin(A[i+3]) - sin(A[i+1]) * A[i+2]) > eps) return false; } return true; } int main () { int cas; scanf("%d", &cas); while (cas--) { int S = 0, C = 0, E = 0; bool flag = false; for (int i = 0; i < 6; i++) { scanf("%lf", &A[i]); if (A[i] > 0) { S++; if (i&1) C++; else E++; } } if (S < 3) { printf("Invalid input.\n"); continue; } while (S < 6) { int T = S; if (C == 2) { CornerToCorner(); S++, C = 3; } if (E == 3) { EdgeToCorner(); S += 3 - C, C = 3; } for (int i = 0; i < 6; i += 2) { if (A[i] > 0 && A[i+1] > 0) { for (int j = 0; j < 6; j += 2) { if ((A[j] > 0 && A[j+1] > 0) || (A[j] < 0 && A[j+1] < 0)) continue; if (A[j] < 0) { A[j] = A[i] / sin(A[i+1]) * sin(A[j+1]); //printf("%lf %lf!!!!!\n", A[i] / sin(A[i+1]), A[j] / sin(A[j+1])); S++, E++; } else { if (A[i+1] < pi / 2 && A[i] < A[j] && A[i] > A[j] * sin(A[i+1])) flag = true; double tmp = sin(A[i+1]) * A[j] / A[i]; if (tmp > 1 || tmp < 0) continue; A[j+1] = asin(sin(A[i+1]) * A[j] / A[i]); S++, C++; } } } } if (E == 2) { for (int i = 0; i < 6; i += 2) { if (A[i] < 0 && A[i+1] > 0) { A[i] = getEdge(A[(i+2)%6], A[(i+4)%6], A[i + 1]); S++, E++; } } } if (T == S) break; } //printf("%d\n", S); /* for (int i = 0; i < 6; i++) printf("%lf%c", A[i], i == 5 ? '\n' : ' '); */ if (judge()) { if (flag) printf("More than one solution.\n"); else { for (int i = 0; i < 6; i++) printf("%lf%c", A[i], i == 5 ? '\n' : ' '); } } else printf("Invalid input.\n"); } return 0; }
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时间: 2024-10-25 00:21:56