Broken Keyboard UVA 11988 数组实现链表

这个构造十分巧妙,,,又学到一招，有点类似数组实现的邻接表

#include <iostream>
#include <string.h>
#include <cstdio>
#include <math.h>
#define SIGMA_SIZE 26
#pragma warning ( disable : 4996 )

using namespace std;
typedef long long LL;

inline int Max(int a,int b) { return a>b?a:b; }
inline int Min(int a,int b) { return a>b?b:a; }
inline int gcd( int a, int b ) { return b==0?a:gcd(b,a%b); }
inline int lcm( int a, int b ) { return a/gcd(a,b)*b; }  //a*b = gcd*lcm
const int inf = 0x3f3f3f3f;
const int maxn = 1e5+5;
const int maxk = 2e6+5;

char str[maxn];
int nxt[maxn];
int cur, last;


void init()
{
    memset( nxt, 0, sizeof(nxt) );
    cur = last = 0;
}
int main()
{
    while (~scanf("%s", str+1))
    {
        init();
        int len = strlen(str+1);
        nxt[0] = 0;

        for ( int i = 1; i <= len; i++ )
        {
            char ch = str[i];
            if( ch == '[' ) cur = 0;
            else if ( ch == ']' ) cur = last;
            else {
                nxt[i] = nxt[cur];
                nxt[cur] = i;
                if( cur == last ) last = i;
                cur = i;
            }
        }
        for( int i = nxt[0]; i; i = nxt[i] )
            printf( "%c", str[i] );
        printf( "
" );
    }
}