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Submission #1078981

# Submission time Handle Problem Language Result Execution time Memory
1078981 2024-08-28T08:57:40 Z Neco_arc Palinilap (COI16_palinilap) C++17
100 / 100
 75 ms 25868 KB 
#include <bits/stdc++.h>
#ifdef LOCAL
#include <bits/debug.hpp>
#endif // LOCAL

#define ll long long
#define all(x) x.begin(), x.end()
#define Neco "Palinilap"
#define resp(x) sort(all(x)), x.resize(unique(all(x)) - x.begin())
#define getbit(x,i) ((x >> i)&1)
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r
#define cntbit(x) __builtin_popcountll(x)
#define fi(i, a, b) for(int i = a; i <= b; i++)
#define fid(i, a, b) for(int i = a; i >= b; i--)
#define maxn (int) 2e5 + 7

using namespace std;

const ll mod = 1e9 + 7; //972663749
const ll base = 911382323;

int n;
string s;
ll H[2][maxn], po[maxn];
ll P[maxn][26], Sum;

struct BIT {
    ll bit[maxn];

    void update(int l, int r, ll val) {
        for(   ; l < maxn; l += (l & -l)) bit[l] += val;
        for(++r; r < maxn; r += (r & -r)) bit[r] -= val;
    }

    ll get(int x, ll ans = 0) {
        for(; x > 0; x -= (x & -x)) ans += bit[x];
        return ans;
    }

} Tsiz, Tval;

bool same(int x, int y, int u, int v) {
    ll P1 = (H[0][y] - H[0][x - 1] * po[y - x + 1] + mod * mod) % mod;
    ll P2 = (H[1][u] - H[1][v + 1] * po[v - u + 1] + mod * mod) % mod;
    return P1 == P2;
}

int Find(int x, int u) {
    int l = 1, r = min(x, n - u + 1);
    while(l <= r) {
        int mid = (l + r) >> 1;
        if(same(x - mid + 1, x, u, u + mid - 1)) l = mid + 1;
        else r = mid - 1;
    }
    return r;
}

void solve()
{

    cin >> s;
    n = s.size(), s = ' ' + s;

    fi(i, 1, n)  H[0][i] = (H[0][i - 1] * base + s[i]) % mod;
    fid(i, n, 1) H[1][i] = (H[1][i + 1] * base + s[i]) % mod;

    fi(i, 1, n) { /// odd len
        int len = Find(i, i); Sum += len;
        int l = i - len + 1, r = i + len - 1;

        Tsiz.update(l, i - 1, 1), Tsiz.update(i + 1, r, -1);
        Tval.update(l, i - 1, 1 - l), Tval.update(i + 1, r, r + 1);

        --l, ++r;
        if(1 <= l && r <= n) {
            int k = Find(l - 1, r + 1) + 1;
            P[l][s[r] - 'a'] += k, P[r][s[l] - 'a'] += k;
        }
    }

    fi(i, 1, n - 1) { /// even len
        int len = Find(i, i + 1); Sum += len;
        int l = i - len + 1, r = i + len;

        Tsiz.update(l, i, 1), Tsiz.update(i + 1, r, -1);
        Tval.update(l, i, 1 - l), Tval.update(i + 1, r, r + 1);

        --l, ++r;
        if(1 <= l && r <= n) {
            int k = Find(l - 1, r + 1) + 1;
            P[l][s[r] - 'a'] += k, P[r][s[l] - 'a'] += k;
        }
    }

    ll ans = Sum;
    fi(i, 1, n) {
        ll bad = Tsiz.get(i) * i + Tval.get(i);
        fi(t, 0, 25) ans = max(ans, Sum - bad + P[i][t]);
    }

    cout << ans;

}


int main()
{

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    if(fopen(Neco".inp", "r")) {
        freopen(Neco".inp", "r", stdin);
        freopen(Neco".out", "w", stdout);
    }

    po[0] = 1;
    fi(i, 1, maxn - 2) po[i] = po[i - 1] * base % mod;

    int nTest = 1;
//    cin >> nTest;


    while(nTest--)
    {
        solve();
    }


    return 0;
}

Compilation message

palinilap.cpp: In function 'int main()':
palinilap.cpp:115:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  115 |         freopen(Neco".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
palinilap.cpp:116:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  116 |         freopen(Neco".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2136 KB Output is correct
2 Correct 2 ms 2140 KB Output is correct
3 Correct 2 ms 2036 KB Output is correct
4 Correct 2 ms 2140 KB Output is correct
5 Correct 2 ms 2140 KB Output is correct

Subtask #2
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 3164 KB Output is correct
2 Correct 4 ms 3164 KB Output is correct
3 Correct 5 ms 3164 KB Output is correct
4 Correct 4 ms 2652 KB Output is correct
5 Correct 4 ms 3120 KB Output is correct
6 Correct 5 ms 3300 KB Output is correct
7 Correct 5 ms 3164 KB Output is correct

Subtask #3
46.0 / 46.0

# Verdict Execution time Memory Grader output
1 Correct 62 ms 25688 KB Output is correct
2 Correct 64 ms 25844 KB Output is correct
3 Correct 61 ms 25628 KB Output is correct
4 Correct 75 ms 25676 KB Output is correct
5 Correct 69 ms 25868 KB Output is correct
6 Correct 72 ms 25768 KB Output is correct
7 Correct 67 ms 25680 KB Output is correct
8 Correct 48 ms 5460 KB Output is correct
9 Correct 66 ms 25840 KB Output is correct
10 Correct 64 ms 25864 KB Output is correct
11 Correct 60 ms 25680 KB Output is correct
12 Correct 71 ms 25676 KB Output is correct
13 Correct 65 ms 25688 KB Output is correct
14 Correct 64 ms 25684 KB Output is correct
15 Correct 64 ms 25688 KB Output is correct
16 Correct 68 ms 25692 KB Output is correct
17 Correct 57 ms 25680 KB Output is correct
18 Correct 58 ms 25680 KB Output is correct
19 Correct 56 ms 25848 KB Output is correct