Nyoj 5 Binary String Matching

题目来源：http://acm.nyist.net/JudgeOnline/problem.php?pid=5

修正的nextval写法：

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

const int MAXN = 1010;
const int MAXM = 11;

int nextval[MAXM];

void Get_NextVal(char* str)
{
    int Len  = strlen(str);
    int i = 0, j = -1;
    nextval[0] = -1;
    while(i < Len)
    {
        if(j == -1 || str[i] == str[j])
        {
            ++i, ++j;
            if(str[i] == str[j])
                nextval[i] = nextval[j];
            else
                nextval[i] = j;
        }
        else
            j = nextval[j];
    }
}

int KMP(char* str1, char* str2, int ans)
{
    int Len1 = strlen(str1);
    int Len2 = strlen(str2);
    int i = 0, j = 0;
    Get_NextVal(str1);
    while(i < Len2)
    {
        if(j == -1 || str2[i] == str1[j])
            ++i, ++j;
        else
            j = nextval[j];
        if(j >= Len1)
        {
            ans++;
            j = nextval[j];
        }
    }
    return ans;
}

int main()
{
    char str1[MAXM], str2[MAXN];
    int T;
    scanf("%d", &T);
    while(T--)
    {
        scanf("%s", str1);
        scanf("%s", str2);
        printf("%d\n", KMP(str1, str2, 0));
    }
    return 0;
}

非修正：

#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

const int MAXN = 1010;
const int MAXM = 11;

int next[MAXM];

void Get_Next(char* str)
{
    int Len = strlen(str);
    int i = 0, j = -1;
    next[0] = -1;
    while(i < Len)
    {
        if(j == -1 || str[i] == str[j])
        {
            ++i, ++j;
            next[i] = j;//表示下一个与i向匹配的位置
        }
        else
            j = next[j];
    }
}

int KMP(char* str1, char* str2, int ans)
{
    int Len1, Len2;
    Len1 = strlen(str1);
    Len2 = strlen(str2);
    int i = 0, j = 0;
    Get_Next(str1);
    while(i < Len2)
    {
        if(j == -1 || str2[i] == str1[j])
            ++i, ++j;
        else
            j = next[j];

        if(j >= Len1)
        {
            ans++;
            j = next[j];
        }
    }
    return ans;
}

int main()
{
    int T;
    char str1[MAXM], str2[MAXN];
    scanf("%d", &T);
    while(T--)
    {
        scanf("%s", str1);
        scanf("%s", str2);
        printf("%d\n", KMP(str1, str2, 0));
    }
    return 0;
}