[Lyndon分解] HDU 6761 Minimum Index (2020多校训练)

Posted 2020-12-18 aemshana

[Lyndon分解] HDU 6761 Minimum Index (2020多校训练)

题解

待补。

Code

#include <iostream>
#include <algorithm>
#include <cstring>
#include <string>
#include <cstdio>
#include <vector>
using namespace std;

#define RG register int
#define LL long long

const LL MOD=1000000007LL;
LL Mul[1000010];
int Pos[1000010];
char str[1000010];
int T,N;

void Lyndon(char *s,int len){
    int i=1,j,k;
    while(i<=len){
        Pos[i]=i;
        for(j=i,k=i+1;k<=len && s[j]<=s[k];++k){
            if(j==i) Pos[k-1]=i;
            else Pos[k-1]=Pos[j-1]+k-j;
            if(s[j]<s[k]) j=i;
            else ++j;
        }
        while(i<=j){Pos[i+k-j-1]=i;i+=k-j;}
    }
    return;
}

int main(){
    Mul[0]=1;
    for(RG i=1;i<=1000000;++i)
        Mul[i]=Mul[i-1]*1112LL%MOD;
    scanf("%d",&T);
    while(T--){
        scanf("%s",str+1);
        N=strlen(str+1);
        Lyndon(str,N); 
        LL Ans=0;
        for(RG i=1;i<=N;++i)
            Ans=(Ans+(LL)Pos[i]*Mul[i-1]%MOD)%MOD;
        printf("%lld
",Ans);
    }
    return 0;
}