【模板】字符串hash

洛谷P3370

 1 #include<cstdio>
 2 #include<cstring>
 3 #include<iostream>
 4 #include<algorithm>
 5 #define sz 10010
 6 #define ull unsigned long long
 7 using namespace std;
 8 int n, ans = 1;
 9 const int base = 233;
10 ull a[sz];
11 char s[sz];
12 ull hash(char s[]) {
13     int len = strlen(s);
14     ull ans = 0;
15     for(int i = 0; i < len; i++) ans = (ans*base+(ull)s[i]);
16 //一度不理解它怎么就转换成base进制的数了qaq不想承认自己是个傻子qaq
17     return ans&0x7ffffff;
18 }
19 int main() {
20     scanf("%d",&n);
21     for(int i = 1; i <= n; i++) {
22         scanf("%s",s);
23         a[i] = hash(s);
24     }
25     sort(a+1,a+n+1);
26     for(int i = 2; i <= n; i++) if(a[i] != a[i-1]) ans++;
27     printf("%d",ans);
28     return 0;
29 } 

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