Submission #433551

#	Time	Username	Problem	Language	Result	Execution time	Memory
433551		misir	Palindromes (APIO14_palindrome)	C++14	0 / 100	42 ms	68684 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;
#define INF 1<<30
#define endl '\n'
#define maxn 100005
#define tc prllf("Case %d: ", cs)
#define tcn prllf("Case %d:\n", cs);
#define FASTIO ios_base::sync_with_stdio(false), cin.tie(0), cout.tie(0);
typedef long long ll;
const double PI = acos(-1.0);


#define si(x) scanf("%d",&x)
#define sii(x,y) scanf("%d %d",&x,&y)
#define siii(x,y,z) scanf("%d %d %d",&x,&y,&z)
#define sl(x) scanf("%lld",&x)
#define sll(x,y) scanf("%lld %lld",&x,&y)
#define slll(x,y,z) scanf("%lld %lld %lld",&x,&y,&z)
#define ss(ch) scanf("%s",ch)
#define pi(x) printf("%d",x)
#define pii(x,y) printf("%d %d",x,y)
#define piii(x,y,z) printf("%d %d %d",x,y,z)
#define pl(x) printf("%lld",x)
#define pll(x,y) printf("%lld %lld",x,y)
#define plll(x,y,z) printf("%lld %lld %lld",x,y,z)
#define ps(ch) printf("%s",ch)
#define F(i,a,b)      for(int i= a; i <= b; i++)
#define R(i,b,a)      for(int i= b; i >= a; i--)
#define REP(i,n) for(int i = 0; i < (n); i++)
#define sline(a) scanf("%[^\n]s",a)
#define Case(t) printf("Case %d:\n",t)

const ll N = 300005;
ll idx, t;
ll link[N];
ll len[N];
ll tr[N][26];
// string s;
char s[N];
ll occ[N];

void initTree()
{
    memset(tr, 0, sizeof tr);
    memset(link, 0, sizeof link);
    memset(len, 0, sizeof len);

    len[1] = -1;
    link[1] = 1;
    len[2] = 0;
    link[2] = 1;
    idx = 2;
    t = 2;
}

void addletter(ll pos)
{
    while (s[pos - len[t] - 1] != s[pos]) t = link[t];
    ll x = link[t];
    while (s[pos - len[x] - 1] != s[pos]) x = link[x];
    ll c = s[pos] - 'a';
    if (!tr[t][c]) {
        tr[t][c] = ++idx;
        len[idx] = len[t] + 2;
        link[idx] = len[idx] == 1 ? 2 : tr[x][c];
    }
    t = tr[t][c];
    occ[t]++;
}


//https://vjudge.net/problem/HDU-3948
int main()
{

    /*
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
    freopen("error.txt", "w", stderr);
#endif
    //*/
    // ll T;
    // scanf("%d", &T);
    // T = 1;
    // for (ll cs = 1; cs <= T; cs++) {
    initTree();
    // cin >> s;
    // s = ' ' + s;
    // ll n = s.size();
    scanf("%s", s);
    int n = strlen(s);
    // cerr << n << "\n";
    char last;
    for (int i = 0; i < n - 1; i++) {
        last = s[i + 1];
        s[i + 1] = s[i];
    }
    s[n] = last;
    s[0] = ' ';
    // cerr << n << "\n";
    for (ll i = 1; i <= n; i++) {
    // cerr << s[i] << "\n";
        addletter(i);
    }
    // prllf("Case #%d: %d\n", cs, idx - 2);
    // }

    // for (ll i = idx; i > 2; i--)

    ll ans = 0;
    for (ll i = idx; i > 2; i--) {
        occ[link[i]] += occ[i];
        ans = max(ans, len[i] * occ[i]);
    }
    // cout << ans << "\n";
    pl(ans);
    printf("\n");
    return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:91:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |     scanf("%s", s);
      |     ~~~~~^~~~~~~~~
palindrome.cpp:99:10: warning: 'last' may be used uninitialized in this function [-Wmaybe-uninitialized]
   99 |     s[n] = last;
      |     ~~~~~^~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27