Submission #1123706

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123706		gdragon	Palindromic Partitions (CEOI17_palindromic)	C++20	35 / 100	133 ms	196608 KiB

palindromic

#include <bits/stdc++.h>
using namespace std;
#define TASK "long"
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define GETBIT(mask, i) ((mask) >> (i) & 1)
#define MASK(i) ((1LL) << (i))
#define SZ(x) ((int)(x).size())
#define mp make_pair
#define CNTBIT(mask) __builtin_popcount(mask)
template<class X, class Y> bool maximize(X &x, Y y){ if (x < y) {x = y; return true;} return false;};
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y) {x = y; return true;} return false;};
typedef pair<int, int> ii;
const int N = 1e6 + 5;
const int inf = 1e9 + 7;
const long long INF = (long long)1e18 + 7;
// const int mod = 1e9 + 7;
// void add(int &x, int y) {x += y; if (x >= mod) x -= mod;}
// void sub(int &x, int y) {x -= y; if (x < 0) x += mod;}
// int mul(int x, int y) {return 1LL * x * y % mod;}
// -----------------------------------------//
const pair<int, int> mod = {1e9 + 7, 1e9 + 9};
const pair<int, int> base = {31, 311};
ii operator + (const ii &x, const ii &y) {
    return {(x.fi + y.fi) % mod.fi, (x.se + y.se) % mod.se};
}
ii operator - (const ii &x, const ii &y) {
    return {(x.fi - y.fi + mod.fi) % mod.fi, (x.se - y.se + mod.se) % mod.se};
}
ii operator * (const ii &x, const ii &y) {
    return {1LL * x.fi * y.fi % mod.fi, 1LL * x.se * y.se % mod.se};
}
pair<int, int> pw[N];
int n;
pair<int, int> hs[N];
string s;
void read() {
    cin >> s;
    n = SZ(s);
    s = ' ' + s;
}
pair<int, int> getHash(int l, int r) {
    return hs[r] - hs[l - 1] * pw[r - l + 1];
}
int f[10002][10002];
int calDp(int l, int r) {
    if (l > r) return 0;
    if (f[l][r]) return f[l][r];
    int &res = f[l][r];
    res = 1;
    for(int i = 0; l + i < r - i ; i++) {
        if (getHash(l, l + i) == getHash(r - i, r)) {
            res = max(res, calDp(l + i + 1, r - i - 1) + 2);
            // cerr << l << ' ' << r << ' ' << i << endl;
        }
    }
    return res;
}
void solve() {
    for(int i = 1; i <= n; i++) {
        pair<int, int> c = {s[i] - 'a' + 1, s[i] - 'a' + 1};
        hs[i] = hs[i - 1] * base + c;
    }
    if (n <= 10000) {
        for(int i = 1; i <= n; i++) {
            for(int j = 1; j <= n; j++) f[i][j] = 0;
        }
        cout << calDp(1, n) << endl;
    }
}
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
    pw[0] = {1, 1};
    for(int i = 1; i < N; i++) pw[i] = pw[i - 1] * base; 
    int test = 1;
    cin >> test;
    while(test--) {
        read();
        solve();
    }
    return 0;
}

Compilation message (stderr)

palindromic.cpp: In function 'int main()':
palindromic.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
palindromic.cpp:78:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 20 / 20
• Subtask 3: 0 / 25
• Subtask 4: 0 / 40