![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
class Congruent_Linear_Equation_Group { private: #define MAX_GROUP_SIZE 10 int groupSize, dis; int A[MAX_GROUP_SIZE], M[MAX_GROUP_SIZE]; int gcd(int a, int b) { int k; while (b != 0) { k = b; b = a % b; a = k; } return a; } /* * * * * * * * * * * a,b=>x,y * * ax+by=gcd(a,b) * * * * * * * * * * */ int extended_gcd(int a, int b, int &x, int &y) { int ans, t; if (b == 0) { x = 1; y = 0; return a; } else { ans = extended_gcd(b, a % b, x, y); t = x; x = y; y = t - (a / b) * y; } return ans; } public: Congruent_Linear_Equation_Group() { groupSize = 0; } void clear() { groupSize = 0; } void addEquation(int a, int m) { if (m == 0) { return; } A[groupSize] = a; M[groupSize++] = m; } // => Possible solution,not minium positive solution int getSolution() { int at = A[0], mt = M[0], ap, mp, x, y, z; for (int i = 1; i < groupSize; i++) { ap = A[i]; mp = M[i]; if ((at - ap) % gcd(mt, mp) != 0) { return -1; } /* * * * * * * * * * * * * * x=mt*y+at * * x=mp*z+ap * * => at-ap=mp*z-mt*y * * * * * * * * * * * * * */ extended_gcd(mp, -1 * mt, z, y); // => mp*z-mt*y=gcd(mp,-mt) z = z * (at - ap) / gcd(mp, -mt); x = mp * z + ap; mt = mt * mp / gcd(mt, mp); while (x <= 0) { x += mt; } at = x; } dis = mt; return x; } int getNextSolution(int x) { return x + dis; } };
clear():清空数据结构
addEquation():向方程组中添加一个方程
getSolution():求出方程组的一个解
getNextSolution():求出当前可行解的下一个可行解
getLastSolution():求出当前可行解的上一个可行解