#include <iostream> using namespace std; long long int mod = 1000000007; long long int binom(int n, int k) { if(k == 0){ return 1; } if(n == 0){ return 0; } long long int res = 1LL; if (k > n - k) k = n - k; for (int i = 0; i < k; ++i) { res *= (long long int) (n - i); res /= (long long int) (i + 1); res %= mod; } return res; } int getDist(string s1, string s2) { int c = 0; for (int i = 0; i < s1.length(); i++) { if (s1[i] != s2[i]) { c++; } } return c; } long long int getVolume(int r, int dist) { long long int res = 0; for (int i = 0; i <= r; i++) { res += binom(dist, i); res %= mod; } return res; } long long int getIntersection(int r1, int r2, int len, int dist) { //cout<<" "<<dist<<"\n"; if(dist == 0){ return getVolume(min(r1, r2), len); } long long int res = 0; for (int i = 0; i <= r1; i++) { for (int j = 0; j <= r2; j++) { if(((dist + i - j) % 2 == 0) && (i + j >= dist)) { //cout<<" "<<i<<" "<<j<<" "<<(len-dist)<<" "<<(dist + i - j) / 2<<" "<<(dist - i - j) / 2<<" "<<binom(dist, (dist + i - j) / 2)<<" "<< binom((len - dist), (dist - i - j) / 2)<<"\n"; res += binom(dist, (dist + i - j) / 2) * binom((len - dist), (dist - i - j) / 2); res %= mod; } } } return res; } int main() { ios_base::sync_with_stdio(false); int n; cin >> n; int r1, r2, r3; string s1, s2, s3; cin >> r1 >> s1 >> r2 >> s2 >> r3 >> s3; long long int res = 0; if(s1 == s2){ if(r1 > r2){ res += getVolume(r1, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r1, r3, n, getDist(s1, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } else{ res += getVolume(r2, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r2, r3, n, getDist(s2, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } } if(s1 == s3){ if(r1 > r3){ res += getVolume(r1, n); res += getVolume(r2, n); res %= mod; res -= getIntersection(r1, r2, n, getDist(s1, s2)); if(res < 0){ res += mod; } cout<<res; return 0; } else{ res += getVolume(r2, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r2, r3, n, getDist(s2, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } } if(s2 == s3){ if(r2 > r3){ res += getVolume(r1, n); res += getVolume(r2, n); res %= mod; res -= getIntersection(r1, r2, n, getDist(s1, s2)); if(res < 0){ res += mod; } cout<<res; return 0; } else{ res += getVolume(r1, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r1, r3, n, getDist(s1, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } } res += getVolume(r1, n); //cout<<getVolume(r1, s1)<<"\n"; res += getVolume(r2, n); // cout<<getVolume(r2, s2)<<"\n"; res %= mod; res += getVolume(r3, n); // cout<<getVolume(r3, s3)<<"\n"; res %= mod; res -= getIntersection(r1, r2, n, getDist(s1, s2)); // cout<<getIntersection(r1, r2, n, getDist(s1, s2))<<"\n"; if(res < 0){ res += mod; } res -= getIntersection(r1, r3, n, getDist(s1, s3)); //cout<<getIntersection(r1, r3, n, getDist(s1, s3))<<"\n"; if(res < 0){ res += mod; } res -= getIntersection(r2, r3, n, getDist(s2, s3)); //cout<<getIntersection(r2, r3, n, getDist(s2, s3))<<"\n"; if(res < 0){ res += mod; } cout<<res; return 0; }
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 | #include <iostream> using namespace std; long long int mod = 1000000007; long long int binom(int n, int k) { if(k == 0){ return 1; } if(n == 0){ return 0; } long long int res = 1LL; if (k > n - k) k = n - k; for (int i = 0; i < k; ++i) { res *= (long long int) (n - i); res /= (long long int) (i + 1); res %= mod; } return res; } int getDist(string s1, string s2) { int c = 0; for (int i = 0; i < s1.length(); i++) { if (s1[i] != s2[i]) { c++; } } return c; } long long int getVolume(int r, int dist) { long long int res = 0; for (int i = 0; i <= r; i++) { res += binom(dist, i); res %= mod; } return res; } long long int getIntersection(int r1, int r2, int len, int dist) { //cout<<" "<<dist<<"\n"; if(dist == 0){ return getVolume(min(r1, r2), len); } long long int res = 0; for (int i = 0; i <= r1; i++) { for (int j = 0; j <= r2; j++) { if(((dist + i - j) % 2 == 0) && (i + j >= dist)) { //cout<<" "<<i<<" "<<j<<" "<<(len-dist)<<" "<<(dist + i - j) / 2<<" "<<(dist - i - j) / 2<<" "<<binom(dist, (dist + i - j) / 2)<<" "<< binom((len - dist), (dist - i - j) / 2)<<"\n"; res += binom(dist, (dist + i - j) / 2) * binom((len - dist), (dist - i - j) / 2); res %= mod; } } } return res; } int main() { ios_base::sync_with_stdio(false); int n; cin >> n; int r1, r2, r3; string s1, s2, s3; cin >> r1 >> s1 >> r2 >> s2 >> r3 >> s3; long long int res = 0; if(s1 == s2){ if(r1 > r2){ res += getVolume(r1, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r1, r3, n, getDist(s1, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } else{ res += getVolume(r2, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r2, r3, n, getDist(s2, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } } if(s1 == s3){ if(r1 > r3){ res += getVolume(r1, n); res += getVolume(r2, n); res %= mod; res -= getIntersection(r1, r2, n, getDist(s1, s2)); if(res < 0){ res += mod; } cout<<res; return 0; } else{ res += getVolume(r2, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r2, r3, n, getDist(s2, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } } if(s2 == s3){ if(r2 > r3){ res += getVolume(r1, n); res += getVolume(r2, n); res %= mod; res -= getIntersection(r1, r2, n, getDist(s1, s2)); if(res < 0){ res += mod; } cout<<res; return 0; } else{ res += getVolume(r1, n); res += getVolume(r3, n); res %= mod; res -= getIntersection(r1, r3, n, getDist(s1, s3)); if(res < 0){ res += mod; } cout<<res; return 0; } } res += getVolume(r1, n); //cout<<getVolume(r1, s1)<<"\n"; res += getVolume(r2, n); // cout<<getVolume(r2, s2)<<"\n"; res %= mod; res += getVolume(r3, n); // cout<<getVolume(r3, s3)<<"\n"; res %= mod; res -= getIntersection(r1, r2, n, getDist(s1, s2)); // cout<<getIntersection(r1, r2, n, getDist(s1, s2))<<"\n"; if(res < 0){ res += mod; } res -= getIntersection(r1, r3, n, getDist(s1, s3)); //cout<<getIntersection(r1, r3, n, getDist(s1, s3))<<"\n"; if(res < 0){ res += mod; } res -= getIntersection(r2, r3, n, getDist(s2, s3)); //cout<<getIntersection(r2, r3, n, getDist(s2, s3))<<"\n"; if(res < 0){ res += mod; } cout<<res; return 0; } |