Cipher Message

Cipher Message

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把字符串相邻相同的字符去掉，直至没法再去除为止，暴力模拟就好了
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#include <cstdio>
#include <cstring>
char a[200010];
int nextt[200010], pre[200010];

int main()
{
    scanf("%s", a);
    int n = strlen(a);
    int first = 0;
    for (int i = 0; i < n; i++)
    {
        nextt[i] = i + 1; pre[i + 1] = i;
    }
    for (int i = first; nextt[i] < n && i < n; i = nextt[i])
    {
        while (a[i] == a[nextt[i]])
        {
            if (nextt[i] >= n || i >= n) break;
            int q = pre[i];
            if (i == first)
            {
                first = nextt[nextt[i]];
                i = first;
                continue;
            }
            else
            {
                nextt[pre[i]] = nextt[nextt[i]];
                pre[nextt[nextt[i]]] = pre[i];
            }
            i = q;
        }
    }
    for (int i = first; i < n; i = nextt[i])
    {
        printf("%c", a[i]);
    }
    printf("\n");
}