str2int
Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 131072/131072 K (Java/Others)
Total Submission(s): 1568 Accepted Submission(s): 540
Problem Description
In this problem, you are given several strings that contain only digits from ‘0‘ to ‘9‘, inclusive.
An example is shown below.
101
123
The set S of strings is consists of the N strings given in the input file, and all the possible substrings of each one of them.
It‘s boring to manipulate strings, so you decide to convert strings in S into integers.
You can convert a string that contains only digits into a decimal integer, for example, you can convert "101" into 101, "01" into 1, et al.
If an integer occurs multiple times, you only keep one of them.
For example, in the example shown above, all the integers are 1, 10, 101, 2, 3, 12, 23, 123.
Your task is to calculate the remainder of the sum of all the integers you get divided by 2012.
Input
There are no more than 20 test cases.
The test case starts by a line contains an positive integer N.
Next N lines each contains a string consists of one or more digits.
It‘s guaranteed that 1≤N≤10000 and the sum of the length of all the strings ≤100000.
The input is terminated by EOF.
Output
An integer between 0 and 2011, inclusive, for each test case.
Sample Input
5
101
123
09
000
1234567890
Sample Output
202
Source
2012 Asia Tianjin Regional Contest
题意: n个字符串，对于每一个子串可以表示为一个数字， 求所有子串的数字和相加对2012取模，， 相同数字只算一次。
这题可以先把n个字符串用一个没有出现过的字符隔开连起来。然后求sa， lcp。
我们可以先看一个简单的例子。
s = 12345
num[1] = 1 sum[1] = 1
num[2] = 12 sum[2] = 1 + 12
num[3] = 123 sum[3] = 1 + 12 + 123
num[4] = 1234 sum[4] = 1 + 12 ＋ 123 + 1234
num[5] = 12345 sum[5] = 1 + 12 + 123 + 1234 + 12345
如果求[3, 4] ， 只需要 sum[5] - sum[2] - num[2] * (10 + 100 + 1000)；
判重时 只要从 i+ lcp[rank[i]] 开始算就可以了，，因为公共前缀那一部分 在前面已经算了。
上代码。。
1 #include <set>
2 #include <map>
3 #include <cmath>
4 #include <ctime>
5 #include <queue>
6 #include <stack>
7 #include <cstdio>
8 #include <string>
9 #include <vector>
10 #include <cstdlib>
11 #include <cstring>
12 #include <iostream>
13 #include <algorithm>
14 using namespace std;
15 typedef unsigned long long ull;
16 typedef long long ll;
17 const int inf = 0x3f3f3f3f;
18 const double eps = 1e-8;
19 const int mod = 2012;
20 const int maxn = 2e5+100;
21 int sum [maxn], num[maxn];
22 string s;
23 int sa[maxn], Rank[maxn], tmp[maxn], lcp[maxn];
24 int k, len;
25 bool cmp(int i, int j)
26 {
27 if (Rank[i] != Rank[j])
28 return Rank[i] < Rank[j];
29 else
30 {
31 int x = (i+k <= len ? Rank[i+k] : -1);
32 int y = (j+k <= len ? Rank[j+k] : -1);
33 return x < y;
34 }
35 }
36 void build_sa()
37 {
38 for (int i = 0; i <= len; i++)
39 {
40 sa[i] = i;
41 Rank[i] = (i < len ? s[i] : -1);
42 }
43 for (k = 1; k <= len; k *= 2)
44 {
45 sort (sa,sa+len+1,cmp);
46 tmp[sa[0]] = 0;
47 for (int i = 1; i <= len; i++)
48 {
49 tmp[sa[i]] = tmp[sa[i-1]] + (cmp(sa[i-1],sa[i])? 1 : 0);
50 }
51 for (int i = 0; i <= len; i++)
52 Rank[i] = tmp[i];
53 }
54 }
55
56 void Get_lcp()
57 {
58 for (int i = 0; i < len; i++)
59 Rank[sa[i]] = i;
60 int h = 0;
61 lcp[0] = 0;
62 for (int i = 0; i < len; i++)
63 {
64 int j = sa[Rank[i]-1];
65 if (h > 0)
66 h--;
67 for (; h+i < len && h+j < len; h++)
68 if (s[i+h] != s[j+h])
69 break;
70 lcp[Rank[i]] = h;
71 }
72 }
73 bool isdigit(char &ch)
74 {
75 return ch >= ‘0‘ && ch <= ‘9‘;
76 }
77 int vec[maxn], board[maxn], tot;
78 int SUM[maxn];
79 int solve (int l, int r)
80 {
81 if (l > r)
82 return 0;
83 int res ;
84 res = sum[r] - sum[l-1];
85 res = ((res%mod)+mod)%mod;
86 res -= num[l-1] * SUM[r-l+1];
87 res = ((res%mod)+mod)%mod;
88 return ((res%mod)+mod)%mod;
89 }
90 int main()
91 {
92 #ifndef ONLINE_JUDGE
93 freopen("in.txt","r",stdin);
94 #endif
95 int n;
96 SUM[1] = 10;
97 for (int i = 2; i < maxn; i++)
98 {
99 SUM[i] = (SUM[i-1] + 1) * 10 % mod;
100 }
101 while (~scanf ("%d", &n))
102 {
103 s = "\0";
104 tot = 0;
105 memset(sum, 0, sizeof(sum));
106 memset(num, 0, sizeof(num));
107 for (int i = 0; i < n; i++)
108 {
109 string tmp;
110 cin >> tmp;
111 s += tmp + "#";
112 }
113 len = s.size();
114 int val = 0;
115 for (int i = 0; i < len; i++)
116 {
117 if (s[i] != ‘#‘)
118 {
119 val = (val * 10 + s[i] - ‘0‘) % mod;
120 num[i] = val;
121 sum[i] = (sum[i-1] + num[i]) % mod;
122 board[i] = tot;
123 }
124 if (s[i] == ‘#‘)
125 {
126 vec[tot++] = i;
127 num[i] = val;
128 sum[i] = sum[i-1] + val;
129 }
130 }
131 build_sa();
132 Get_lcp();
133 int ans = 0;
134 for (int i = 0; i < len; i++)
135 {
136 int t1 = i + lcp[Rank[i]];
137 if (s[i] == ‘0‘)
138 continue;
139 if (isdigit(s[i]) && i+lcp[Rank[i]] < vec[board[i]])
140 {
141 int t2 = vec[board[i]] -1;
142 int ans1 = solve(i, t2);
143 int ans2 = solve(i , t1-1);
144 ans = (ans + solve(i, t2) - solve(i, t1-1)) % mod;
145 if (ans < 0)
146 ans += mod;
147 }
148 }
149 printf("%d\n", ans%mod);
150 }
151 return 0;
152 }