1 HDU 1402 A * B Problem Plus

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <algorithm>
 6 #include <queue>
 7 #include <vector>
 8 #include <stack>
 9 #include <map>
10 #include <set>
11 #include <cmath>
12 #include <cctype>
13 #include <ctime>
14 #include <ext/rope>
15 
16 using namespace std;
17 using namespace __gnu_cxx;
18 
19 #define REP(i, n) for (int i = 0; i < (n); ++i)
20 #define eps 1e-9
21 #define SZ(x) ((int)x.size())
22 
23 typedef long long ll;
24 typedef pair<int, int> pii;
25 
26 #define PI acos(-1.0)
27 const int maxn = 1e5 + 10;
28 struct Complex {
29     double x, y;
30     Complex(double _x = 0.0, double _y = 0.0) { x = _x; y = _y; }
31     Complex operator - (const Complex &b) const { return Complex(x - b.x, y - b.y); }
32     Complex operator + (const Complex &b) const { return Complex(x + b.x, y + b.y); }
33     Complex operator * (const Complex &b) const { return Complex(x * b.x - y * b.y, x * b.y + y * b.x); }
34 };
35 char str_A[maxn], str_B[maxn];
36 Complex A[maxn * 4], B[maxn * 4], ans[maxn * 4];
37 int ans_final[maxn * 4], len_final = 0;
38 int N, M, n = 1;
39 
40 void fft(Complex a[], int len, int oper) {
41     for (int i = 1, j = 0; i < len - 1; ++i) {
42         for (int s = len; ~j & s;) { j ^= s >>= 1; }
43         if (i < j) { swap(a[i], a[j]); }
44     }
45     Complex omega_m, omega, t, u;
46     int m, m2;
47     for (int d = 0; (1 << d) < len; ++d) {
48         m = (1 << d); m2 = m << 1;
49         omega_m = Complex(cos(PI / m * oper), sin(PI / m * oper));
50         for (int i = 0; i < len; i += m2) {
51             omega = Complex(1, 0);
52             for (int j = 0; j < m; ++j) {
53                 u = a[i + j]; t = omega * a[i + j + m];
54                 a[i + j] = u + t; a[i + j + m] = u - t;
55                 omega = omega * omega_m;
56             }
57         }
58     }
59     if (oper == -1) { REP(i, N + M - 1) { a[i].x /= len; } }
60 }
61 
62 
63 int main() {
64 #ifdef __AiR_H
65     freopen("in.txt", "r", stdin);
66 //    freopen("out.txt", "w", stdout);
67 #endif // __AiR_H
68     while (scanf("%s %s", str_A, str_B) != EOF) {
69         memset(ans, 0, sizeof(ans)); memset(ans_final, 0, sizeof(ans_final));
70         N = strlen(str_A); M = strlen(str_B); n = 1;
71         while (n < N + M - 1) { n <<= 1; }
72         REP(i, N) { A[i] = Complex(str_A[N - 1 - i] - '0', 0); }
73         for (int i = N; i < n; ++i) { A[i] = Complex(0, 0); }
74         REP(i, M) { B[i] = Complex(str_B[M - 1 - i] - '0', 0); }
75         for (int i = M; i < n; ++i) { B[i] = Complex(0, 0); }
76         fft(A, n, 1); fft(B, n, 1);
77         REP(i, n) { ans[i] = A[i] * B[i]; }
78         fft(ans, n, -1);
79         REP(i, N + M) { ans_final[i] = ans[i].x + 0.5; }
80         REP(i, N + M - 1) { ans_final[i + 1] += ans_final[i] / 10; ans_final[i] %= 10; }
81         len_final = N + M - 1;
82         if (ans_final[len_final]) { ++len_final; }
83         while (ans_final[len_final - 1] == 0 && len_final > 1) { --len_final; }
84         for (int i = len_final - 1; i > 0; --i) { printf("%d", ans_final[i]); } printf("%d\n", ans_final[0]);
85     }
86     return 0;
87 }
View Code

2 HDU 4609 3-idiots

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <algorithm>
 6 #include <queue>
 7 #include <vector>
 8 #include <stack>
 9 #include <map>
10 #include <set>
11 #include <cmath>
12 #include <cctype>
13 #include <ctime>
14 #include <ext/rope>
15 
16 using namespace std;
17 using namespace __gnu_cxx;
18 
19 #define REP(i, n) for (int i = 0; i < (n); ++i)
20 #define eps 1e-9
21 #define SZ(x) ((int)x.size())
22 
23 typedef long long ll;
24 typedef pair<int, int> pii;
25 
26 #define PI acos(-1.0)
27 const int maxn = 1e5 + 10;
28 struct Complex {
29     double x, y;
30     Complex(double _x = 0.0, double _y = 0.0) { x = _x; y = _y; }
31     Complex operator - (const Complex &b) const { return Complex(x - b.x, y - b.y); }
32     Complex operator + (const Complex &b) const { return Complex(x + b.x, y + b.y); }
33     Complex operator * (const Complex &b) const { return Complex(x * b.x - y * b.y, x * b.y + y * b.x); }
34 };
35 int T, n_t, N, M, n;
36 Complex A[maxn * 4], B[maxn * 4], mul[maxn * 4];
37 int a[maxn];
38 ll ans[maxn * 4], sum[maxn * 4];
39 
40 void fft(Complex a[], int len, int oper) {
41     for (int i = 1, j = 0; i < len - 1; ++i) {
42         for (int s = len; ~j & s;) { j ^= s >>= 1; }
43         if (i < j) { swap(a[i], a[j]); }
44     }
45     Complex omega_m, omega, t, u;
46     int m, m2;
47     for (int d = 0; (1 << d) < len; ++d) {
48         m = (1 << d); m2 = m << 1;
49         omega_m = Complex(cos(PI / m * oper), sin(PI / m * oper));
50         for (int i = 0; i < len; i += m2) {
51             omega = Complex(1, 0);
52             for (int j = 0; j < m; ++j) {
53                 u = a[i + j]; t = omega * a[i + j + m];
54                 a[i + j] = u + t; a[i + j + m] = u - t;
55                 omega = omega * omega_m;
56             }
57         }
58     }
59     if (oper == -1) { REP(i, N + M - 1) { a[i].x /= len; } }
60 }
61 void init() {
62     memset(A, 0 ,sizeof(A)); memset(B, 0, sizeof(B));
63     memset(mul, 0, sizeof(mul)); memset(ans, 0, sizeof(ans)); n = 1;
64 }
65 
66 int main() {
67 #ifdef __AiR_H
68     freopen("in.txt", "r", stdin);
69 //    freopen("out.txt", "w", stdout);
70 #endif // __AiR_H
71     scanf("%d", &T);
72     while (T--) {
73         scanf("%d", &n_t); init();
74         for (int i = 1; i <= n_t; ++i) {
75             scanf("%d", &a[i]); ++A[a[i]].x; ++B[a[i]].x;
76         }
77         sort(a + 1, a + n_t + 1); N = M = a[n_t] + 1;
78         while (n < N + M - 1) { n <<= 1; }
79         fft(A, n, 1); fft(B, n, 1);
80         for (int i = 0; i < n; ++i) { mul[i] = A[i] * B[i]; } fft(mul, n, -1);
81         for (int i = 1; i < N + M; ++i) { ans[i] = (ll)(mul[i].x + 0.5); }
82         for (int i = 1; i <= n_t; ++i) { --ans[a[i] + a[i]]; }
83         for (int i = 1; i <= N + M; ++i) { ans[i] /= 2; }
84         for (int i = 1; i <= N + M; ++i) { sum[i] = sum[i - 1] + ans[i]; }
85         ll ans1 = 1ll * n_t * (n_t - 1) * (n_t - 2) / 6, ans2 = 0;
86         for (int i = 1; i <= n_t; ++i) {
87             ans2 += sum[N + M] - sum[a[i]];
88             ans2 -= 1ll * (i - 1) * (n_t - i);
89             ans2 -= n_t - 1;
90             ans2 -= 1ll * (n_t - i) * (n_t - i - 1) / 2;
91         }
92         printf("%.7f\n", 1.0 * ans2 / ans1);
93     }
94     return 0;
95 }
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1 UVALive 4671 K-neighbor substrings

  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cstdlib>
  5 #include <algorithm>
  6 #include <queue>
  7 #include <vector>
  8 #include <stack>
  9 #include <map>
 10 #include <set>
 11 #include <cmath>
 12 #include <cctype>
 13 #include <ctime>
 14 #include <ext/rope>
 15 
 16 using namespace std;
 17 using namespace __gnu_cxx;
 18 
 19 #define REP(i, n) for (int i = 0; i < (n); ++i)
 20 #define eps 1e-9
 21 #define SZ(x) ((int)x.size())
 22 #define PI acos(-1.0)
 23 
 24 typedef long long ll;
 25 typedef unsigned long long ull;
 26 typedef pair<int, int> pii;
 27 const int maxn = 1e5 + 10;
 28 struct Complex {
 29     double x, y;
 30     Complex(double _x = 0.0, double _y = 0.0) { x = _x; y = _y; }
 31     Complex operator - (const Complex &b) const { return Complex(x - b.x, y - b.y); }
 32     Complex operator + (const Complex &b) const { return Complex(x + b.x, y + b.y); }
 33     Complex operator * (const Complex &b) const { return Complex(x * b.x - y * b.y, x * b.y + y * b.x); }
 34 };
 35 ull Hash[maxn], Pow[maxn];
 36 set<ull> s;
 37 int k, len1, len2, Case = 0, N, M, n;
 38 char s1[maxn], s2[maxn];
 39 Complex A[maxn * 4], B[maxn * 4], mul[maxn * 4];
 40 int ans1[maxn * 4], ans2[maxn * 4];
 41 
 42 void fft(Complex a[], int len, int oper) {
 43     for (int i = 1, j = 0; i < len - 1; ++i) {
 44         for (int s = len; ~j & s;) { j ^= s >>= 1; }
 45         if (i < j) { swap(a[i], a[j]); }
 46     }
 47     Complex omega_m, omega, t, u;
 48     int m, m2;
 49     for (int d = 0; (1 << d) < len; ++d) {
 50         m = (1 << d); m2 = m << 1;
 51         omega_m = Complex(cos(PI / m * oper), sin(PI / m * oper));
 52         for (int i = 0; i < len; i += m2) {
 53             omega = Complex(1, 0);
 54             for (int j = 0; j < m; ++j) {
 55                 u = a[i + j]; t = omega * a[i + j + m];
 56                 a[i + j] = u + t; a[i + j + m] = u - t;
 57                 omega = omega * omega_m;
 58             }
 59         }
 60     }
 61     if (oper == -1) { REP(i, N + M - 1) { a[i].x /= len; } }
 62 }
 63 int solve(int ans[], char c) {
 64     memset(A, 0, sizeof(A)); memset(B, 0, sizeof(B));
 65     for (int i = 0; i < len1; ++i) {
 66         if (s1[i] == c) { A[i].x = 1; }
 67     }
 68     for (int i = 0; i < len2; ++i) {
 69         if (s2[i] == c) { B[i].x = 1; }
 70     }
 71     fft(A, n, 1); fft(B, n, 1);
 72     for (int i = 0; i < n; ++i) { mul[i] = A[i] * B[i]; }
 73     fft(mul, n, -1);
 74     for (int i = len2 - 1; i < N + M; ++i) { ans[i] = mul[i].x + 0.5; }
 75 }
 76 
 77 int main() {
 78 #ifdef __AiR_H
 79     freopen("in.txt", "r", stdin);
 80 //    freopen("out.txt", "w", stdout);
 81 #endif // __AiR_H
 82     Pow[0] = 1; ull t; Hash[0] = 0;
 83     for (int i = 1; i < maxn; ++i) { Pow[i] = Pow[i - 1] * 131; }
 84     while (scanf("%d", &k) && k != -1) {
 85         scanf("%s %s", s1, s2); len1 = strlen(s1); len2 = strlen(s2);
 86         if (len1 < len2) { printf("Case %d: 0\n", ++Case); continue; }
 87         reverse(s2, s2 + len2); s.clear();
 88         N = len1; M = len2; n = 1; while (n < N + M - 1) { n <<= 1; }
 89         solve(ans1, 'a'); solve(ans2, 'b');
 90         for (int i = 0; i < len1; ++i) { Hash[i + 1] = Hash[i] * 131 + s1[i]; }
 91         for (int i = 0; i <= len1 - len2; ++i) {
 92             t = Hash[i + len2] - Hash[i] * Pow[len2];
 93             if (len2 - ans1[i + len2 - 1] - ans2[i + len2 - 1] <= k) {
 94                 s.insert(t);
 95             }
 96         }
 97         printf("Case %d: %d\n", ++Case, (int)s.size());
 98     }
 99     return 0;
100 }
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