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Language: Default Period
Description For each prefix of a given string S with N characters (each character has an ASCII code between 97 and 126, inclusive), we want to know whether the prefix is a periodic string. That is, for each i (2 <= i <= N) we want to know the largest K > 1 (if there is Input The input consists of several test cases. Each test case consists of two lines. The first one contains N (2 <= N <= 1 000 000) – the size of the string S.The second line contains the string S. The input file ends with a line, having the number zero on it. Output For each test case, output "Test case #" and the consecutive test case number on a single line; then, for each prefix with length i that has a period K > 1, output the prefix size i and the period K separated by a single space; the prefix sizes must be in increasing Sample Input 3 aaa 12 aabaabaabaab 0 Sample Output Test case #1 2 2 3 3 Test case #2 2 2 6 2 9 3 12 4 Source |
题意：让求哪个子串是由重复的几个串组成的。
解题思路：
next数组~~
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <algorithm>
#define maxn 1000000+10
using namespace std;
int next[maxn];
char P[maxn];
int N;
void getnext()
{
int i=0,j=-1;
next[0]=-1;
while(i<N){
if(j==-1||P[i]==P[j])
next[++i]=++j;
else j=next[j];
}
}
int main()
{
int xp=1;
while(scanf("%d",&N),N){
memset(next,0,sizeof(next));
scanf("%s",P);
getnext();
int l;
printf("Test case #%d\n",xp++);
for(int i=2;i<=N;i++){
l=i-next[i];
if((i%l==0)&&(i/l!=1)){
printf("%d %d\n",i,i/l);
}
}
printf("\n");
}
return 0;
}
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