E - Period

标签：each   style   子序列   cte   ever   fine   ring   tput   ref   

InputThe input file consists of several test cases. Each test case consists of two lines. The first one contains N (2 <= N <= 1 000 000) ?C 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. 
OutputFor 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 order. Print a blank line after each test case. 
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


结论：j%(j-Nex[t])==0 说明该前缀是一个周期为j/(j-Next[j])的周期子序列
证明： j - Next[j] 是子串在失配时候的右移长度，

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<vector>
#include<string>
#include<cstring>
using namespace std;
#define MAXN 1000001
typedef long long LL;
/*
*/
char s[MAXN];
int Next[MAXN];
void kmp_pre(int m)
{
    int j,k;
    j = 0;
    k = -1;
    Next[0] = -1;
    while(j<m)
    {
        if(k==-1||s[j]==s[k])
            Next[++j] = ++k;
        else
            k = Next[k];
    }
}
int main()
{
    int m;
    int cas=1;
    while(scanf("%d",&m),m)
    {
        scanf("%s",s);
        kmp_pre(m);
        printf("Test case #%d\n",cas++);
        for(int i=1;i<=m;i++)
            if((i)%(i-Next[i])==0&&i/(i-Next[i])>1)
                printf("%d %d\n",i,(i)/(i-Next[i]));
        cout<<endl;
    }
}

E - Period

标签：each   style   子序列   cte   ever   fine   ring   tput   ref   

原文地址：http://www.cnblogs.com/joeylee97/p/6674581.html