Submission #95921

#	Time	Username	Problem	Language	Result	Execution time	Memory
95921		Kastanda	Palindromic Partitions (CEOI17_palindromic)	C++11	100 / 100	923 ms	129692 KiB

palindromic

#include<bits/stdc++.h>
using namespace std;
const int MXN = 1000006, SGM = 26;
int n, ts, link[MXN], len[MXN];
int slink[MXN], diff[MXN], sdp[MXN], dp[MXN];
map < int , int > C[MXN];
char S[MXN], _S[MXN];
inline int GetLink(int nw, int i)
{
    while (S[i] != S[i - len[nw] - 1])
        nw = link[nw];
    return (nw);
}
inline int Add(int nw, int i)
{
    int ch = S[i] - 'a';
    nw = GetLink(nw, i);
    if (!C[nw][ch])
    {
        ts ++;
        len[ts] = len[nw] + 2;
        link[ts] = C[GetLink(link[nw], i)][ch];
        diff[ts] = len[ts] - len[link[ts]];
        slink[ts] = link[ts];
        if (diff[ts] == diff[link[ts]])
            slink[ts] = slink[link[ts]];
        C[nw][ch] = ts;
        return (ts);
    }
    return (C[nw][ch]);
}
int main()
{
    int q;
    scanf("%d", &q);
    for (; q; q --)
    {
        memset(_S, 0, sizeof(_S));
        scanf("%s", _S);
        n = strlen(_S);
        for (int i = 1; i < n; i += 2)
        {
            S[i - 1] = _S[i >> 1];
            S[i] = _S[n - 1 - (i >> 1)];
        }
        link[0] = link[1] = 1;
        len[1] = -1; ts = 1;
        sdp[0] = sdp[1] = - MXN;
        dp[0] = 0;
        int nw = 1, Mx = 1;
        for (int i = 1; i <= (n >> 1 << 1); i++)
        {
            dp[i] = - MXN;
            nw = Add(nw, i - 1);
            for (int u = nw; len[u] > 0; u = slink[u])
            {
                sdp[u] = dp[i - len[slink[u]] - diff[u]];
                if (diff[u] == diff[link[u]])
                    sdp[u] = max(sdp[u], sdp[link[u]]);
                if (!(i & 1)) dp[i] = max(dp[i], sdp[u] + 1);
            }
            Mx = max(Mx, dp[i] + dp[i] + (i < n));
        }
        for (int i = 0; i <= ts; i++)
            C[i].clear();
        printf("%d\n", Mx);
    }
    return 0;
}

Compilation message (stderr)

palindromic.cpp: In function 'int main()':
palindromic.cpp:35:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &q);
     ~~~~~^~~~~~~~~~
palindromic.cpp:39:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%s", _S);
         ~~~~~^~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 25 / 25
• Subtask 4: 40 / 40