#include <iostream> #include <vector> #include <algorithm> #include <unordered_map> struct Sphere { int radius; std::string coordinates; }; struct Update { int from; int to; int amount; }; int EditDistance(std::string lhs, std::string rhs) { int diffs = 0; for (int i = 0; i < lhs.size(); i++) { if (lhs[i] != rhs[i]) { diffs++; } } return diffs; } std::vector<int> EditDistance3(std::string c1, std::string c2, std::string c3) { std::vector<int> result; result.emplace_back(0); result.emplace_back(0); result.emplace_back(0); for (int i = 0; i < c1.size(); i++) { if (c1[i] == c2[i]) { if (c1[i] != c3[i]) { result[2]++; // c3 unique } } else { if (c1[i] == c3[i]) { result[1]++; // c2 unique } else { result[0]++; // c1 unique } } } return result; } int min3(int a, int b, int c) { return std::min(a, std::min(b, c)); } constexpr int mod = 1e9 + 7; int main(int argc, char** argv) { int dims; std::cin >> dims; Sphere* spheres = new Sphere[3]; for (int i = 0; i < 3; i++) { std::cin >> spheres[i].radius; std::cin >> spheres[i].coordinates; } std::vector<std::vector<int>> binoms; std::vector<std::vector<int>> binom_sums; for (int i = 0; i <= dims; i++) { binoms.emplace_back(); binom_sums.emplace_back(); int binom_sum = 0; for (int j = 0; j <= i; j++) { if (i == 0) { binoms[i].emplace_back(1); binom_sums[i].emplace_back(1); } else { int binom = 0; if (j > 0) binom += binoms[i - 1][j - 1]; if (j < i) binom += binoms[i - 1][j]; binoms[i].emplace_back(binom % mod); binom_sum += binom % mod; binom_sum %= mod; binom_sums[i].emplace_back(binom_sum); } } } int result = 0; // Single spheres for (int i = 0; i < 3; i++) { result += binom_sums[dims][spheres[i].radius]; result %= mod; } // Common area of two spheres for (int i = 0; i < 3; i++) { for (int j = i + 1; j < 3; j++) { const Sphere& lhs = spheres[i]; const Sphere& rhs = spheres[j]; int edit_distance = EditDistance(lhs.coordinates, rhs.coordinates); for (int e = 0; e <= edit_distance; e++) { if (lhs.radius - e < 0 || rhs.radius - edit_distance + e < 0) { continue; } int min_rad = std::min(lhs.radius - e, rhs.radius - edit_distance + e); min_rad = std::min(min_rad, dims - edit_distance); long long product = ((long long) binom_sums[dims - edit_distance][min_rad]) * ((long long) binoms[edit_distance][e]) % ((long long) mod); result += mod - ((int) product); result %= mod; } } } // Common area of three spheres const Sphere& s0 = spheres[0]; const Sphere& s1 = spheres[1]; const Sphere& s2 = spheres[2]; auto distances = EditDistance3(s0.coordinates, s1.coordinates, s2.coordinates); int remainder = dims - distances[0] - distances[1] - distances[2]; std::unordered_map<int, int> r2_radius_to_count = {}; std::unordered_map<int, int> r01_radius_to_count = {}; std::unordered_map<int, std::vector<Update>> d2_to_update = {}; for (int d0 = 0; d0 <= distances[0]; d0++) { long long mult0 = ((long long) binoms[distances[0]][d0]); for (int d1 = 0; d1 <= distances[1]; d1++) { int count = (int) (mult0 * binoms[distances[1]][d1] % mod); int rad0 = s0.radius - d0 + d1 - distances[1] - distances[2]; int rad1 = s1.radius - d1 + d0 - distances[0] - distances[2]; int rad2 = s2.radius + d0 + d1 - distances[0] - distances[1]; int min_rad = std::min(rad0, rad1); if (rad2 < min_rad) { r2_radius_to_count[rad2] = (r2_radius_to_count[rad2] + count) % mod; } else { r01_radius_to_count[min_rad] = (r01_radius_to_count[min_rad] + count) % mod; int steps = (rad2 - min_rad + 1) / 2; if (steps <= distances[2]) { Update update; update.amount = count; update.from = min_rad; update.to = rad2; d2_to_update[steps].push_back(update); } } } } for (int d2 = 0; d2 <= distances[2]; d2++) { for (const auto& update : d2_to_update[d2]) { r01_radius_to_count[update.from] = (r01_radius_to_count[update.from] + mod - update.amount) % mod; r2_radius_to_count[update.to] = (r2_radius_to_count[update.to] + update.amount) % mod; } for (const auto& entry : r2_radius_to_count) { int radius = entry.first; int actual_radius = std::min(remainder, radius - d2); if (actual_radius < 0) { continue; } int count = entry.second; long long add = ((long long) count) * binoms[distances[2]][d2] % mod * binom_sums[remainder][actual_radius] % mod; result = (result + add) % mod; } for (const auto& entry : r01_radius_to_count) { int radius = entry.first; int actual_radius = std::min(remainder, radius + d2); if (actual_radius < 0) { continue; } int count = entry.second; long long add = ((long long) count) * binoms[distances[2]][d2] % mod * binom_sums[remainder][actual_radius] % mod; result = (result + add) % mod; } } std::cout << result << std::endl; }
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 | #include <iostream> #include <vector> #include <algorithm> #include <unordered_map> struct Sphere { int radius; std::string coordinates; }; struct Update { int from; int to; int amount; }; int EditDistance(std::string lhs, std::string rhs) { int diffs = 0; for (int i = 0; i < lhs.size(); i++) { if (lhs[i] != rhs[i]) { diffs++; } } return diffs; } std::vector<int> EditDistance3(std::string c1, std::string c2, std::string c3) { std::vector<int> result; result.emplace_back(0); result.emplace_back(0); result.emplace_back(0); for (int i = 0; i < c1.size(); i++) { if (c1[i] == c2[i]) { if (c1[i] != c3[i]) { result[2]++; // c3 unique } } else { if (c1[i] == c3[i]) { result[1]++; // c2 unique } else { result[0]++; // c1 unique } } } return result; } int min3(int a, int b, int c) { return std::min(a, std::min(b, c)); } constexpr int mod = 1e9 + 7; int main(int argc, char** argv) { int dims; std::cin >> dims; Sphere* spheres = new Sphere[3]; for (int i = 0; i < 3; i++) { std::cin >> spheres[i].radius; std::cin >> spheres[i].coordinates; } std::vector<std::vector<int>> binoms; std::vector<std::vector<int>> binom_sums; for (int i = 0; i <= dims; i++) { binoms.emplace_back(); binom_sums.emplace_back(); int binom_sum = 0; for (int j = 0; j <= i; j++) { if (i == 0) { binoms[i].emplace_back(1); binom_sums[i].emplace_back(1); } else { int binom = 0; if (j > 0) binom += binoms[i - 1][j - 1]; if (j < i) binom += binoms[i - 1][j]; binoms[i].emplace_back(binom % mod); binom_sum += binom % mod; binom_sum %= mod; binom_sums[i].emplace_back(binom_sum); } } } int result = 0; // Single spheres for (int i = 0; i < 3; i++) { result += binom_sums[dims][spheres[i].radius]; result %= mod; } // Common area of two spheres for (int i = 0; i < 3; i++) { for (int j = i + 1; j < 3; j++) { const Sphere& lhs = spheres[i]; const Sphere& rhs = spheres[j]; int edit_distance = EditDistance(lhs.coordinates, rhs.coordinates); for (int e = 0; e <= edit_distance; e++) { if (lhs.radius - e < 0 || rhs.radius - edit_distance + e < 0) { continue; } int min_rad = std::min(lhs.radius - e, rhs.radius - edit_distance + e); min_rad = std::min(min_rad, dims - edit_distance); long long product = ((long long) binom_sums[dims - edit_distance][min_rad]) * ((long long) binoms[edit_distance][e]) % ((long long) mod); result += mod - ((int) product); result %= mod; } } } // Common area of three spheres const Sphere& s0 = spheres[0]; const Sphere& s1 = spheres[1]; const Sphere& s2 = spheres[2]; auto distances = EditDistance3(s0.coordinates, s1.coordinates, s2.coordinates); int remainder = dims - distances[0] - distances[1] - distances[2]; std::unordered_map<int, int> r2_radius_to_count = {}; std::unordered_map<int, int> r01_radius_to_count = {}; std::unordered_map<int, std::vector<Update>> d2_to_update = {}; for (int d0 = 0; d0 <= distances[0]; d0++) { long long mult0 = ((long long) binoms[distances[0]][d0]); for (int d1 = 0; d1 <= distances[1]; d1++) { int count = (int) (mult0 * binoms[distances[1]][d1] % mod); int rad0 = s0.radius - d0 + d1 - distances[1] - distances[2]; int rad1 = s1.radius - d1 + d0 - distances[0] - distances[2]; int rad2 = s2.radius + d0 + d1 - distances[0] - distances[1]; int min_rad = std::min(rad0, rad1); if (rad2 < min_rad) { r2_radius_to_count[rad2] = (r2_radius_to_count[rad2] + count) % mod; } else { r01_radius_to_count[min_rad] = (r01_radius_to_count[min_rad] + count) % mod; int steps = (rad2 - min_rad + 1) / 2; if (steps <= distances[2]) { Update update; update.amount = count; update.from = min_rad; update.to = rad2; d2_to_update[steps].push_back(update); } } } } for (int d2 = 0; d2 <= distances[2]; d2++) { for (const auto& update : d2_to_update[d2]) { r01_radius_to_count[update.from] = (r01_radius_to_count[update.from] + mod - update.amount) % mod; r2_radius_to_count[update.to] = (r2_radius_to_count[update.to] + update.amount) % mod; } for (const auto& entry : r2_radius_to_count) { int radius = entry.first; int actual_radius = std::min(remainder, radius - d2); if (actual_radius < 0) { continue; } int count = entry.second; long long add = ((long long) count) * binoms[distances[2]][d2] % mod * binom_sums[remainder][actual_radius] % mod; result = (result + add) % mod; } for (const auto& entry : r01_radius_to_count) { int radius = entry.first; int actual_radius = std::min(remainder, radius + d2); if (actual_radius < 0) { continue; } int count = entry.second; long long add = ((long long) count) * binoms[distances[2]][d2] % mod * binom_sums[remainder][actual_radius] % mod; result = (result + add) % mod; } } std::cout << result << std::endl; } |