【CF】207 Div.1 B.Xenia and Hamming

这题目一看很牛逼，其实非常easy。求求最小公倍数，最大公约数，均摊复杂度其实就是O(n)。

 1 /* 356B */
 2 #include <iostream>
 3 #include <string>
 4 #include <map>
 5 #include <queue>
 6 #include <set>
 7 #include <stack>
 8 #include <vector>
 9 #include <deque>
10 #include <algorithm>
11 #include <cstdio>
12 #include <cmath>
13 #include <ctime>
14 #include <cstring>
15 #include <climits>
16 #include <cctype>
17 #include <cassert>
18 #include <functional>
19 #include <iterator>
20 #include <iomanip>
21 using namespace std;
22 //#pragma comment(linker,"/STACK:102400000,1024000")
23
24 #define sti                set<int>
25 #define stpii            set<pair<int, int> >
26 #define mpii            map<int,int>
27 #define vi                vector<int>
28 #define pii                pair<int,int>
29 #define vpii            vector<pair<int,int> >
30 #define rep(i, a, n)     for (int i=a;i<n;++i)
31 #define per(i, a, n)     for (int i=n-1;i>=a;--i)
32 #define clr                clear
33 #define pb                 push_back
34 #define mp                 make_pair
35 #define fir                first
36 #define sec                second
37 #define all(x)             (x).begin(),(x).end()
38 #define SZ(x)             ((int)(x).size())
39 #define lson            l, mid, rt<<1
40 #define rson            mid+1, r, rt<<1|1
41
42 const int maxn = 1e6+5;
43 char s[maxn], d[maxn];
44 int cs[26];
45 int cd[26];
46
47 int main() {
48     ios::sync_with_stdio(false);
49     #ifndef ONLINE_JUDGE
50         freopen("data.in", "r", stdin);
51         freopen("data.out", "w", stdout);
52     #endif
53
54     __int64 n, m;
55
56     scanf("%I64d %I64d", &n, &m);
57     scanf("%s %s", s, d);
58     int slen = strlen(s);
59     int dlen = strlen(d);
60
61     int g = __gcd(slen, dlen);
62     __int64 lcm = 1LL * slen / g * dlen;
63     __int64 n_ = lcm / slen;
64     __int64 m_ = lcm / dlen;
65
66     #ifndef ONLINE_JUDGE
67         printf("n_ = %I64d, m_ = %I64d\n", n_, m_);
68     #endif
69
70     __int64 t = n / n_;
71     __int64 tot;
72
73     __int64 ans = 0;
74     int i, j, k;
75
76     for (i=0; i<g; ++i) {
77         // count s
78         memset(cs, 0, sizeof(cs));
79         for (j=i,tot=0; j<slen; j+=g,++tot) {
80             ++cs[s[j]-‘a‘];
81         }
82         for (j=i; j<dlen; j+=g) {
83             ans += (tot - cs[d[j]-‘a‘]);
84         }
85     }
86
87     ans *= t;
88     printf("%I64d\n", ans);
89
90     #ifndef ONLINE_JUDGE
91         printf("time = %d.\n", (int)clock());
92     #endif
93
94     return 0;
95 }