Codeforces 432D Prefixes and Suffixes

 1 #include<cstdio>
 2 #include<cmath>
 3 #include<algorithm>
 4 #include<cstring>
 5 #include<iostream>
 6 char s[200005];
 7 int n,p[200005],c[200005],dp[200005];
 8 int read(){
 9     int t=0,f=1;char ch=getchar();
10     while (ch<‘0‘||ch>‘9‘){if (ch==‘-‘) f=-1;ch=getchar();}
11     while (‘0‘<=ch&&ch<=‘9‘){t=t*10+ch-‘0‘;ch=getchar();}
12     return t*f;
13 }
14 int main(){
15     scanf("%s",s+1);
16     n=strlen(s+1);
17     p[1]=0;int j=0;
18     for (int i=2;i<=n;i++){
19         while (j>0&&s[j+1]!=s[i]) j=p[j];
20         if (s[j+1]==s[i]) j++;
21         p[i]=j;
22     }
23     int tot=0;
24     for (int i=p[n];i;i=p[i]){
25         c[++tot]=i;
26     }
27     for (int i=n;i;i--){
28         dp[i]++;
29         dp[p[i]]+=dp[i];
30     }
31     printf("%d\n",tot+1);
32     for (int i=tot;i>=1;i--){
33         printf("%d %d\n",c[i],dp[c[i]]);
34     }
35     printf("%d 1\n",n);
36     return 0;
37 }