poj 3693 重复次数最多的子串

#include<stdio.h>#include<iostream>#include<string.h>#include<algorithm>using namespace std;const int nMax=100005;int r[nMax],a[nMax];int sa[nMax], rank[nMax], height[nMax];int wa[nMax], wb[nMax], wv[nMax], wd[nMax];int cmp(int *r, int a, int b, int l){    return r[a] == r[b] && r[a+l] == r[b+l];}void da(int *r, int n, int m){          //  倍增算法 r为待匹配数组  n为总长度(包含结尾的0） m为字符范围    int i, j, p, *x = wa, *y = wb, *t;    for(i = 0; i < m; i ++) wd[i] = 0;    for(i = 0; i < n; i ++) wd[x[i]=r[i]] ++;    for(i = 1; i < m; i ++) wd[i] += wd[i-1];    for(i = n-1; i >= 0; i --) sa[-- wd[x[i]]] = i;    for(j = 1, p = 1; p < n; 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 < n; i ++) wv[i] = x[y[i]];        for(i = 0; i < m; i ++) wd[i] = 0;        for(i = 0; i < n; i ++) wd[wv[i]] ++;        for(i = 1; i < m; i ++) wd[i] += wd[i-1];        for(i = n-1; i >= 0; i --) sa[-- wd[wv[i]]] = y[i];        for(t = x, x = y, y = t, p = 1, x[sa[0]] = 0, i = 1; i < n; i ++)        {            x[sa[i]] = cmp(y, sa[i-1], sa[i], j) ? p - 1: p ++;        }    }}void calHeight(int *r, int n){           //  求height数组。    int i, j, k = 0;    for(i = 1; i <= n; i ++) rank[sa[i]] = i; // 1->n    for(i = 0; i < n; i++){        for(k ? k -- : 0, j = sa[rank[i]-1]; r[i+k] == r[j+k]; k ++);        height[rank[i]] = k;    }}int Log[nMax],dp[nMax][20];void initRMQ(int n){    // 求log2(x)    Log[0]=-1;    for(int i=1;i<=nMax;i++)        Log[i]=(i&(i-1))?Log[i-1]:Log[i-1]+1;    for(int i=1;i<=n;i++) dp[i][0]=height[i];    for(int j=1;j<=Log[n];j++)        for(int i=1;i+(1<<j)-1<=n;i++)        {            dp[i][j]=min(dp[i][j-1],dp[i+(1<<(j-1))][j-1]);        }}int lcp(int x,int y){    int a=rank[x],b=rank[y];    if(a>b) swap(a,b);    a++;    int k=Log[b-a+1];    return min(dp[a][k],dp[b-(1<<k)+1][k]);}int main(){//    freopen("test.txt","r",stdin);    char s[nMax]; int num=0;    while(scanf("%s",s) && s[0]!='#')    {        int n=strlen(s);num++;        for(int i=0;i<n;i++) r[i]=s[i]-'a'+1;        r[n]=0;        da(r,n+1,27);        calHeight(r,n);        initRMQ(n);        int ret=0,cnt=0,flag=0;        for(int len=1;len<=n;len++)        {            for(int j=len;j<=n;j+=len)            {                int lc=lcp(j-len,j),m=len-lc%len;                if(j>len && (lc%len))                    lc=max(lc,lcp(j-len-m,j-m));                lc=lc/len+1;                if(lc>ret)                {                    ret=lc; cnt=0;                    a[cnt++]=len;                }                else if(lc==ret && a[cnt-1]!=len) a[cnt++]=len;            }        }        for(int i=1;i<=n;i++)        {           for(int j=0;j<cnt;j++)                if(lcp(sa[i],sa[i]+a[j])>=a[j]*(ret-1))                {                    flag=1;                    printf("Case %d: ",num);                    for(int k=0;k<a[j]*ret;k++)                        printf("%c",s[k+sa[i]]);                    printf("\n");                    break;                }            if(flag) break;        }    }    return 0;}