标签：扩展kmp

A + B for you again

asdf sdfg
asdf ghjk

asdfg
asdfghjk

Statistic | Submit | Discuss | Note

这题我是用扩展kmp做的, 做两次就行

/*************************************************************************
    > File Name: hdu1867.cpp
    > Author: ALex
    > Mail: zchao1995@gmail.com 
    > Created Time: 2015年02月02日 星期一 17时03分34秒
 ************************************************************************/

#include <map>
#include <set>
#include <queue>
#include <stack>
#include <vector>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;

const double pi = acos(-1);
const int inf = 0x3f3f3f3f;
const double eps = 1e-15;
typedef long long LL;
typedef pair <int, int> PLL;

const int N = 200110;

char S[N], T[N];
int next[N];
int extend[N];
char A1[N], A2[N];

void EXTEND_KMP (char S[], char T[])
{
	int lens = strlen (S);
	int lent = strlen (T);
	next[0] = lent;
	int i, j, p, L;
	j = 0;
	while (j + 1 < lent && T[j] == T[j + 1]) // 先求出next[1]
	{
		++j;
	}
	next[1] = j;
	int a = 1;
	for (i = 2; i < lent; ++i)
	{
		p = next[a] + a - 1;
		L = next[i - a];
		if (i + L < p + 1)
		{
			next[i] = L;
		}
		else
		{
			j = max (0, p - i + 1);
			while (i + j < lent && T[i + j] == T[j])
			{
				++j;
			}
			next[i] = j;
			a = i;
		}
	}
	j = 0;
	while (j < lens && S[j] == T[j])
	{
		++j;
	}
	extend[0] = j;
	a = 0;
	for (i = 1; i < lens; ++i)
	{
		p = extend[a] + a - 1;
		L = next[i - a];
		if (L + i < p + 1)
		{
			extend[i] = L;
		}
		else
		{
			j = max(0, p - i + 1);
			while (i + j < lens && j < lent && S[i + j] == T[j])
			{
				++j;
			}
			extend[i] = j;
			a = i;
		}
	}
}

int main ()
{
	while (~scanf("%s%s", S, T))
	{
		EXTEND_KMP (S, T);
		int lens = strlen (S);
		int lent = strlen (T);
		int s = -1;
		strcpy (A1, S);
		for (int i = 0; i < lens; ++i)
		{
			if (extend[i] + i == lens)
			{
				s = i;
				break;
			}
		}
		if (s == -1)
		{
			strcat (A1, T);
		}
		else
		{
			int cnt = lens;
			for (int i = lens - s; i < lent; ++i)
			{
				A1[cnt++] = T[i];
			}
			A1[cnt] = '\0';
		}
		memset (next, 0, sizeof(next));
		memset (extend, 0, sizeof(extend));
		strcpy (A2, T);
		EXTEND_KMP (T, S);
		s = -1;
		for (int i = 0; i < lent; ++i)
		{
			if (extend[i] + i == lent)
			{
				s = i;
				break;
			}
		}
		if (s == -1)
		{
			strcat (A2, S);
		}
		else
		{
			int cnt = lent;
			for (int i = lent - s; i < lens; ++i)
			{
				A2[cnt++] = S[i];
			}
			A2[cnt] = '\0';
		}
		int len1 = strlen (A1);
		int len2 = strlen (A2);
		if (len1 < len2)
		{
			printf("%s\n", A1);
		}
		else if (len1 > len2)
		{
			printf("%s\n", A2);
		}
		else
		{
			if (strcmp (A1, A2) < 0)
			{
				printf("%s\n", A1);
			}
			else
			{
				printf("%s\n", A2);
			}
		}
	}
	return 0;
}

hdu1867---A + B for you again

标签：扩展kmp

原文地址：http://blog.csdn.net/guard_mine/article/details/43411631