kejpmdt's blog

By kejpmdt, history, 4 months ago, In English
#include <bits/stdc++.h>
using namespace std;
void radixsort(vector<pair<pair<int, int>, int>> &a)
{
    int n = a.size();
    {
        vector<int> cnt(n);
        for (auto x : a)
        {
            cnt[x.first.second]++;
        }
        vector<pair<pair<int, int>, int>> a_new(n);
        vector<int> pos(n);
        pos[0] = 0;
        for (int i = 1; i <= n; ++i)
        {
            pos[i] = pos[i - 1] + cnt[i - 1];
        }
        for (auto x : a)
        {
            int i = x.first.second;
            a_new[pos[i]] = x;
            pos[i]++;
        }
        a = a_new;
    }
    {
        vector<int> cnt(n);
        for (auto x : a)
        {
            cnt[x.first.first]++;
        }
        vector<pair<pair<int, int>, int>> a_new(n);
        vector<int> pos(n);
        pos[0] = 0;
        for (int i = 1; i <= n; ++i)
        {
            pos[i] = pos[i - 1] + cnt[i - 1];
        }
        for (auto x : a)
        {
            int i = x.first.first;
            a_new[pos[i]] = x;
            pos[i]++;
        }
        a = a_new;
    }
}
int main()
{
    string s;
    cin >> s;
    s += "$";
    int n = s.size();
    vector<int> p(n), c(n);
    {
        vector<pair<char, int>> a(n);
        for (int i = 0; i < n; ++i)
        {
            a[i] = {s[i], i};
        }
        sort(a.begin(), a.end());
        for (int i = 0; i < n; ++i)
        {
            p[i] = a[i].second;
        }
        c[p[0]] = 0;
        for (int i = 1; i < n; ++i)
        {
            if (a[i].first == a[i - 1].first)
            {
                c[p[i]] = c[p[i - 1]];
            }
            else
            {
                c[p[i]] = c[p[i - 1]] + 1;
            }
        }
    }
    int k = 0;
    while ((1 << k) < n)
    {
        vector<pair<pair<int, int>, int>> a(n);
        for (int i = 0; i < n; ++i)
        {
            a[i] = {{c[i], c[(i + (1 << k)) % n]}, i};
        }
        radixsort(a);
        for (int i = 0; i < n; ++i)
        {
            p[i] = a[i].second;
        }
        c[p[0]] = 0;
        for (int i = 1; i < n; ++i)
        {
            if (a[i].first == a[i - 1].first)
            {
                c[p[i]] = c[p[i - 1]];
            }
            else
            {
                c[p[i]] = c[p[i - 1]] + 1;
            }
        }
        k++;
    }
    for (int i = 0; i < n; ++i)
    {
        cout << p[i] << ' ';
    }
    return 0;
}

All of the probable error will be in the function called radixsort ,the other part doesn't have any error.

Could anyone tell me where the error is?

The original code could be found in the Suffix Array of the edu.

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