Codeforces Round #422 (Div. 2) E. Liar 后缀数组+RMQ+DP

#include<bits/stdc++.h>
using namespace std;
#pragma comment(linker, "/STACK:102400000,102400000")
#define ls i<<1
#define rs ls | 1
#define mid ((ll+rr)>>1)
#define pii pair<int,int>
#define MP make_pair
typedef long long LL;
const long long INF = 1e18+1LL;
const double pi = acos(-1.0);
const int N = 5e5+5, M = 1e3+20,inf = 2e9+10;

int *ran,r[N],sa[N],height[N],wa[N],wb[N],wm[N];
bool cmp(int *r,int a,int b,int l) {
    return r[a] == r[b] && r[a+l] == r[b+l];
}
void SA(int *r,int *sa,int n,int m) {
    int *x=wa,*y=wb,*t;
    for(int i=0;i<m;++i)wm[i]=0;
    for(int i=0;i<n;++i)wm[x[i]=r[i]]++;
    for(int i=1;i<m;++i)wm[i]+=wm[i-1];
    for(int i=n-1;i>=0;--i)sa[--wm[x[i]]]=i;
    for(int i=0,j=1,p=0;p<n;j=j*2,m=p){
        for(p=0,i=n-j;i<n;++i)y[p++]=i;
        for(i=0;i<n;++i)if(sa[i]>=j)y[p++]=sa[i]-j;
        for(i=0;i<m;++i)wm[i]=0;
        for(i=0;i<n;++i)wm[x[y[i]]]++;
        for(i=1;i<m;++i)wm[i]+=wm[i-1];
        for(i=n-1;i>=0;--i)sa[--wm[x[y[i]]]]=y[i];
        for(t=x,x=y,y=t,i=p=1,x[sa[0]]=0;i<n;++i) {
            x[sa[i]]=cmp(y,sa[i],sa[i-1],j)?p-1:p++;
        }
    }
    ran=x;
}
void Height(int *r,int *sa,int n) {
    for(int i=0,j=0,k=0;i<n;height[ran[i++]]=k)
    for(k?--k:0,j=sa[ran[i]-1];r[i+k] == r[j+k];++k);
}
int dp[N][30];
int n,m,f[N][33];
char s[N],t[N];
void Lcp_init() {
    for(int i = 1; i <= n+m+1; ++i)
        dp[i][0] = height[i];
    for(int j = 1; (1<<j) <= n + m + 1; ++j) {
        for(int i = 1; i + (1<<j) - 1 <= n+m-1; ++i) {
            dp[i][j] = min(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);
        }
    }
}
int lcp(int l,int r) {
    l = ran[l], r = ran[r];
    if(l > r) swap(l,r);
    ++l;
    int len = r - l + 1;
    int k = 0;
    while((1<<(k+1)) <= len) ++k;
    return min(dp[l][k], dp[r - (1<<k) + 1][k]);
}
int main() {
    scanf("%d%s%d%s",&n,s,&m,t);
    for(int i = 0; i < n; ++i) r[i] = s[i] - ‘a‘ + 1;
    r[n] = ‘*‘;
    for(int i = n+1; i < m+n+1; ++i) r[i] = t[i - n - 1] - ‘a‘ + 1;
    r[n+m+1] = 0;
    SA(r,sa,n+m+1+1,256);
    Height(r,sa,n+m+1);
    Lcp_init();
    int X;
    scanf("%d",&X);
    int mx = 0;
    for(int i = 0; i <= n; ++i) {
        for(int j = 0; j <= X; ++j) {
            f[i+1][j] = max(f[i+1][j],f[i][j]);
            int t = lcp(i,f[i][j] + n + 1);
            f[i + t][j+1] = max(f[i + t][j+1] , f[i][j] + t);
            mx = max(f[i][j],mx);
        }
    }
    if(mx == m) puts("YES");
    else puts("NO");
    return 0;
}