序列自動機學習

序列自動機一個可以n*(字符集)的複雜度預處理出字符串第i位及以後第一次出現大於字符j的位置

原理 if x>j  dp[i][j]=i;

       else dp[i][j]=dp[i+1][j];

#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<cstring>
#include<string>
#include<stack>
#include<queue>
#include<deque>
#include<set>
#include<vector>
#include<map>

#define fst first
#define sc second
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define lson l,mid,root<<1
#define rson mid+1,r,root<<1|1
#define lc root<<1
#define rc root<<1|1
#define lowbit(x) ((x)&(-x))

using namespace std;

typedef double db;
typedef long double ldb;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> PI;
typedef pair<ll,ll> PLL;

const db eps = 1e-6;
const int mod = 1e9+7;
const int maxn = 1e6+100;
const int maxm = 2e6+100;
const int inf = 0x3f3f3f3f;
const db pi = acos(-1.0);
char a[maxn];
int d[maxn][27];
int main()
{
    scanf("%s",a+1);
    int len=strlen(a+1);
    for(int i=1;i<=len;i++)
    {
        int x=a[i]-'a';
        for(int j=0;j<='z'-'a';j++)
        {
            if(x>j)d[i][j]=i;
            else d[i][j]=d[i+1][j];
        }
    }
    return 0;
}