标签：hash
字符串hash模板，
本题是求，给定字符串s中至少出现m次的最长字符串长度，及此时起始位置的最大值
白书p225
//#pragma warning (disable: 4786)
//#pragma comment (linker, "/STACK:16777216")
//HEAD
#include <cstdio>
#include <ctime>
#include <cstdlib>
#include <cstring>
#include <queue>
#include <string>
#include <set>
#include <stack>
#include <map>
#include <cmath>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
//LOOP
#define FE(i, a, b) for(int i = (a); i <= (b); ++i)
#define FD(i, b, a) for(int i = (b); i>= (a); --i)
#define REP(i, N) for(int i = 0; i < (N); ++i)
#define CLR(A,value) memset(A,value,sizeof(A))
#define CPY(a, b) memcpy(a, b, sizeof(a))
#define FC(it, c) for(__typeof((c).begin()) it = (c).begin(); it != (c).end(); it++)
//INPUT
#define RI(n) scanf("%d", &n)
#define RII(n, m) scanf("%d%d", &n, &m)
#define RIII(n, m, k) scanf("%d%d%d", &n, &m, &k)
#define RS(s) scanf("%s", s)
//OUTPUT
#define WI(n) printf("%d\n", n)
#define WS(s) printf("%s\n", s)
const int INF = 0x3f3f3f3f;
#define ULL unsigned long long
const int maxn = 40010;
const int SEED = 13331;
int n, m;
int rank[maxn];
char s[maxn];
ULL xp[maxn];
ULL hashs[maxn];
int pos;
ULL ha[maxn];
int cmp(const int &a, const int &b)///cmp注意
{
return ha[a] < ha[b] || (ha[a] == ha[b] && a < b);
}
int possible(int L)
{
for (int i = 0; i < n - L + 1; i++)
{
rank[i] = i;
///
ha[i] = hashs[i] - hashs[i + L] * xp[L];
}
sort(rank, rank + n - L + 1, cmp);
int x;
pos = -1;
for (int i = 0; i < n - L + 1; i++)
{
if (i == 0 || ha[rank[i]] != ha[rank[i - 1]]) x = 0;
if (++x >= m) pos = max(pos, rank[i]);
}
return pos >= 0;
}
int main()
{
///
xp[0] = 1;
for (int i = 1; i < maxn; i++)
xp[i] = xp[i - 1] * SEED;
while (cin >> m && m)
{
RS(s);
n = strlen(s);
///
hashs[n] = 0;
for (int i = n - 1; i >= 0; i--)
hashs[i] = hashs[i + 1] * SEED + s[i];
if (!possible(1)) puts("none");
else
{
int L = 1, R = n;
while (L <= R)
{
int M = (L + R) >> 1;
if (possible(M)) L = M + 1;
else R = M - 1;
}
possible(R);
printf("%d %d\n", R, pos);
}
}
return 0;
}
LA 4513 Stammering Aliens 字符串hash,布布扣,bubuko.com
LA 4513 Stammering Aliens 字符串hash
标签：hash
原文地址：http://blog.csdn.net/guognib/article/details/24935991
