思路:求最大最小表示的位置,直接模板,求次数的话,先用KMP求出循环节的大小,再判断一下,最大最小表示出现次数相同,具体看代码注释。
AC code:
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<string>
#include<cstring>
using namespace std;
const int maxn = 1e6 + 10;
string str;
int len = 0;
int nex[maxn];
void make_nex(){//KMP的nex数组
int j = 0,k = -1;
nex[0] = -1;
while(j <= len){
if(k == -1 || str[k] == str[j]){
if(str[k+1] == str[j+1]){
nex[j+1] = nex[k+1];
++j,++k;
}else{
nex[j+1] = k+1;
++j,++k;
}
}else{
k = nex[k];
}
}
}
int min_rep(){
int i = 1,j = 0,k = 0;
while(j < len && i < len){
k = 0; //之前这个忘记写了
while(str[(i+k) % len] == str[(j+k) % len] && k < len){
++k;
}
if(k == len){
return min(i,j) + 1;
}
if(str[(i+k)%len] > str[(j+k)%len]){
i = max(i+k+1, j+1);
}else{
j = max(j + k + 1, i + 1);
}
}
return min(i,j) + 1;
}
int max_rep(){
int i = 1,j = 0,k = 0;
while(j < len && i < len){
k = 0;
while(str[(i+k) % len] == str[(j+k) % len] && k < len){
++k;
}
if(k == len){
return min(i,j) + 1;
}
if(str[(i+k)%len] < str[(j+k)%len]){
i = max(i+k+1, j+1) ;
}else{
j = max(j + k + 1, i + 1);
}
}
return min(i,j) + 1;
}
int main(){
while(cin >> str){
len = str.size();
memset(nex,0,sizeof(nex));
make_nex(); //之前忘记,调用函数了,也忘记了初始化
int min_pos = min_rep();
int max_pos = max_rep();
int min_times = 0,max_times = 0;
int r = len - nex[len];//求循环节的大小
//cout << "enm " << r << endl;
if(len % r == 0){//别忘记判断,要的是纯净的循环,全有循环节组成,不含杂质
min_times = max_times = len / r;
}else{
min_times = max_times = 1;
}
//cout << min_rep() << endl;
cout << min_pos << " " << min_times << " " << max_pos << " " << max_times << endl;
}
return 0;
}