poj 2774 Long Long Message

 第一个后缀数组，拍模版……

/* * Author: stormdpzh * Created Time: 2012/7/22 14:22:35 * File Name: poj_2774.cpp */#include <iostream>#include <cstdio>#include <sstream>#include <cstring>#include <string>#include <cmath>#include <vector>#include <queue>#include <stack>#include <map>#include <set>#include <algorithm>#include <functional>#define sz(v) ((int)(v).size())#define rep(i, n) for(int i = 0; i < n; i++)#define repf(i, a, b) for(int i = a; i <= b; i++)#define repd(i, a, b) for(int i = a; i >= b; i--)#define out(n) printf("%d\n", n)#define mset(a, b) memset(a, b, sizeof(a))#define wh(n) while(1 == scanf("%d", &n))#define whz(n) while(1 == scanf("%d", &n) && n != 0)#define lint long longusing namespace std;const int MaxN = 200005;char s[MaxN];int n;int sa[MaxN], height[MaxN], rank[MaxN], tmp[MaxN], top[MaxN];void makesa(){    int na = n < 256 ? 256 : n;    mset(top, 0);    rep(i, n) top[rank[i] = s[i] & 0xff]++;    repf(i, 1, na - 1) top[i] += top[i - 1];    rep(i, n) sa[--top[rank[i]]] = i;    for(int len = 1; len < n; len <<= 1) {        int j;        rep(i, n) {            j = sa[i] - len;            if(j < 0) j += n;            tmp[top[rank[j]]++] = j;        }        sa[tmp[top[0] = 0]] = j = 0;        repf(i, 1, n - 1) {            if(rank[tmp[i]] != rank[tmp[i - 1]] || rank[tmp[i] + len] != rank[tmp[i - 1] + len])                top[++j] = i;            sa[tmp[i]] = j;        }        memcpy(rank, sa, n * sizeof(int));        memcpy(sa, tmp, n * sizeof(int));        if(j >= n - 1) break;    }}void lcp(){    int i, j, k;    for(j = rank[height[i = k = 0] = 0]; i < n - 1; i++, k++)        while(k >= 0 && s[i] != s[sa[j - 1] + k]) {            height[j] = (k--);            j = rank[sa[j] + 1];        }}bool check(int i, int len){    if(sa[i] < len && sa[i - 1] < len) return false;    if(sa[i] > len && sa[i - 1] > len) return false;    return true;}int main(){    while(1 == scanf("%s", s)) {        int len = strlen(s);        s[len] = 2;        n = len;        scanf("%s", s + n + 1);        n = strlen(s);        s[n] = 1;        n++;        makesa();        lcp();        int res = 0;        rep(i, n) if(res < height[i] && check(i, len))            res = height[i];        printf("%d\n", res);    }             return 0;}