POJ2752 KMP中next數組的應用

這裏寫鏈接內容

    #include <iostream>  
    #include <cstdio>  
    #include <cstring>  
    using namespace std;  

    int Next[400005];  
    char str[400005];  
    int ans[400005];  
    int cnt;  
    int len;  

    void getNext()  
    {  
        Next[0] = -1;  
        int i = 0, j = -1;  
        while (i < len)  
        {  
            if (j == -1 || str[i] == str[j])  
            {  
                ++i;  
                ++j;  
                Next[i] = j;  
            }  
            else j = Next[j];  
        }  
    }  

    int main()  
    {  
        while (scanf("%s", str) != EOF)  
        {  
            len = strlen(str);  
            getNext();  
            for(int i=0;i<=len;i++){
                cout<<Next[i]<<" ";
            }cout<<endl;
            cnt = 0;  
            int t = Next[len - 1];  
            while (t != -1)  
            {  
                if (str[t] == str[len - 1]) ans[cnt++] = t + 1;  
                t = Next[t];  
            }  
            for (int i = cnt - 1; i >= 0; --i)  
            {  
                printf("%d ", ans[i]);  
            }  
            printf("%d\n", len);  
        }  
        return 0;  
    }