codeforces #336 div 2 B. Hamming Distance Sum
http://codeforces.com/contest/608/problem/B 题意：给定两个字符串a,b，问b中的每个连续的长度为a的子串与a的哈密顿距离的和是多少。哈密顿距离是对应位置的字符的差的绝对值的和。由于是01串，也就是字符不同的位置数。 思路：类似前缀和。0和1分别搞。注意开long long
1/* ***********************************************
2Author :111qqz
3Created Time :2015年12月24日 星期四 00时32分33秒
4File Name :code/cf/#336/B.cpp
5************************************************ */
6
7#include <cstdio>
8#include <cstring>
9#include <iostream>
10#include <algorithm>
11#include <vector>
12#include <queue>
13#include <set>
14#include <map>
15#include <string>
16#include <cmath>
17#include <cstdlib>
18#include <ctime>
19#define fst first
20#define sec second
21#define lson l,m,rt<<1
22#define rson m+1,r,rt<<1|1
23#define ms(a,x) memset(a,x,sizeof(a))
24typedef long long LL;
25#define pi pair < int ,int >
26#define MP make_pair
27
28using namespace std;
29const double eps = 1E-8;
30const int dx4[4]={1,0,0,-1};
31const int dy4[4]={0,-1,1,0};
32const int inf = 0x3f3f3f3f;
33const int N=3E5+7;
34int la,lb;
35char a[N],b[N];
36int sum0[N],sum1[N];
37int main()
38{
39 #ifndef ONLINE_JUDGE
40 freopen("code/in.txt","r",stdin);
41 #endif
42 ms(sum0,0);
43 ms(sum1,0);
44 scanf("%s",a);
45 scanf("%s",b);
46 la = strlen(a);
47 lb = strlen(b);
48 int sum = 0 ;
49 if (la==1)
50 {
51 for ( int i = 0 ; i < lb ; i++)
52 {
53 if (b[i]!=a[0]) sum++;
54 }
55 cout<<sum<<endl;
56 return 0;
57
58 }
59
60 for ( int i = 0 ; i < lb ; i++)
61 {
62 if (b[i]=='0')
63 {
64 sum0[i+1] = sum0[i]+1;
65 sum1[i+1] = sum1[i];
66 }
67 else
68 {
69 sum1[i+1] = sum1[i] +1;
70 sum0[i+1] = sum0[i];
71 }
72 }
73// for ( int i = 1 ; i <= lb ; i++)
74// cout<<sum0[i]<<" "<<sum1[i]<<endl;
75 LL ans = 0;
76 for (int i= 0 ; i < la ; i++)
77 {
78 if (a[i]=='0')
79 {
80 ans+=LL(sum1[lb-la+i+1]-sum1[i]);
81 }
82 else
83 {
84 ans+=LL(sum0[lb-la+i+1]-sum0[i]);
85 }
86// cout<<ans<<endl;
87 }
88
89 cout<<ans<<endl;
90
91 #ifndef ONLINE_JUDGE
92 fclose(stdin);
93 #endif
94 return 0;
95}