hdu 3518 Boring counting 后缀数组LCP

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN = 1007;
char s[MAXN];
int sa[MAXN],t[MAXN],t2[MAXN],c[MAXN],n;
void build_sa(int m,int n) // m为字符ASCII码的最大值+1;n = strlen(s) + 1;
{
    int i,*x = t, *y = t2;
    for(i = 0;i < m; i++) c[i] = 0;
    for(i = 0;i < n; i++) c[x[i] = s[i]]++;
    for(i = 1;i < m; i++) c[i] += c[i-1];
    for(i = n - 1;i >= 0; i--) sa[--c[x[i]]] = i;
    for(int k = 1;k <= n;k <<= 1){
        int p = 0;
        for(i = n - k;i < n;i++) y[p++] = i;
        for(i = 0;i < n;i++) if(sa[i] >= k) y[p++] = sa[i] - k;

        for(i = 0;i < m;i++) c[i] = 0;
        for(i = 0;i < n;i++) c[x[y[i]]]++;
        for(i = 1;i < m;i++) c[i] += c[i-1];
        for(i = n - 1;i >= 0;i--) sa[--c[x[y[i]]]] = y[i];

        swap(x,y);
        x[sa[0]] = 0;// 将字符彻底转变为序号;
        for(i = 1,p = 1;i < n;i++)
            x[sa[i]] = y[sa[i]] == y[sa[i-1]] && y[sa[i]+k] == y[sa[i-1]+k]?p-1:p++;
        if(p >= n) break;
        m = p;
    }
}
int rk[MAXN],height[MAXN];
void getHeight()
{
    int i,j,k = 0;
    for(i = 1;i <= n;i++) rk[sa[i]] = i; // rk[i]:后缀i在sa[]中的下标,从1开始
    for(i = 0;i < n;i++){
        if(k) k--;
        if(rk[i] == 0) continue;
        j = sa[rk[i] - 1];
        while(i+k<n && j+k<n && s[i+k] == s[j+k]) k++;
        height[rk[i]] = k; // h[i] = height[rk[i]]; h[i] >= h[i-1] - 1;
    }
}
int main()
{
    while(scanf("%s",s) == 1 && s[0] != ‘#‘){
        ll ans = 0;
        n = strlen(s);
        s[n] = ‘#‘;
        build_sa(‘z‘+1,n+1);
        getHeight();
        for(int i = 1;i <= n/2; i++){
            int l = n+1,r = -1;
            for(int j = 2;j <= n;j++){
                if(height[j] >= i){// 递推出最左最优的l,r;
                    r = max(r,max(sa[j],sa[j-1]));
                    l = min(l,min(sa[j],sa[j-1]));
                }
                else{
                    if(r-l >= i) ans++;
                    r = -1,l = n+1;
                }
            }
            if(r-l >= i) ans++;
        }
        printf("%I64d\n",ans);
    }
    return 0;
}