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Submission #539065

# Submission time Handle Problem Language Result Execution time Memory
539065 2022-03-18T10:47:17 Z cpp219 Palinilap (COI16_palinilap) C++17
100 / 100
 66 ms 25908 KB 
#include<bits/stdc++.h>
#define ll long long
#define ld long double
#define fs first
#define sc second
#define debug(y) cout<<y,exit(0)
using namespace std;
typedef pair<ll,ll> LL;
const ll N = 1e5 + 9;
const ll base = 31;
const ll mod = 1e9 + 7;

ll n,Hash[N][2],pw[N],have[2][N],creat[N][26],ans,got[N];
string s[2];

void performHash(){
    for (ll i = 1;i <= n;i++)
        for (ll j = 0;j < 2;j++){
            Hash[i][j] = Hash[i - 1][j]*base + s[j][i] - 'a' + 1;
            Hash[i][j] %= mod;
        }
}

ll GetHash(ll l,ll r,ll c){
    return (Hash[r][c] - Hash[l - 1][c]*pw[r - l + 1] + mod*mod)%mod;
}

bool IsPalin(ll l,ll r){
    return GetHash(l,r,0) == GetHash(n - r + 1,n - l + 1,1);
}

int main(){
    ios_base::sync_with_stdio(NULL); cin.tie(0); cout.tie(0);
    #define task "test"
    if (fopen(task".inp","r")){
        freopen(task".inp","r",stdin);
        freopen(task".out","w",stdout);
    }
    cin>>s[0]; n = s[0].size();
    s[1] = s[0]; reverse(s[1].begin(),s[1].end());
    s[0] = " " + s[0]; s[1] = " " + s[1];
    performHash(); pw[0] = 1;
    for (ll i = 1;i <= n;i++) pw[i] = (pw[i - 1]*base) % mod;
    //debug(IsPalin(1,3));
    for (ll i = 1;i <= n;i++)
        for (ll j = i;j <= i + 1;j++){
            //if (j > n || s[0][i] != s[0][j]) continue;
            ll l = (s[0][i] == s[0][j]),h = min(i,n - j + 1),m;
            while(l <= h){
                m = (l + h)/2;
                if (IsPalin(i - m + 1,j + m - 1)) l = m + 1;
                else h = m - 1;
            }
            ll rad = h; ans += rad; //debug(rad);
            have[0][i]++; have[0][i - rad]--;
            have[1][j]++; have[1][j + rad]--;
            if (i == j) got[i] += rad - 1;
            if (i - rad <= 0 || j + rad > n) continue;
            l = 0; h = min(i - rad - 1,n - j - rad);
            ll x = i - rad,y = j + rad;
            while(l <= h){
                m = (l + h)/2;
                ll kq1 = GetHash(x - m,x - 1,0);
                ll kq2 = GetHash(n - y - m + 1,n - y,1);
                if (kq1 == kq2) l = m + 1;
                else h = m - 1;
            }
            //debug(h);
            //cout<<x<<" "<<y; return 0;
            creat[x][s[0][y] - 'a'] += h + 1;
            creat[y][s[0][x] - 'a'] += h + 1;
        }
    //debug(creat[2]['c' - 'a']);
    //for (ll i = 1;i <= n;i++) cout<<have[0][i]<<" "; cout<<"\n";
    for (ll i = 2;i <= n;i++) have[1][i] += have[1][i - 1];
    //for (ll i = 1;i <= n;i++) cout<<have[0][i]<<" "; return 0;
    for (ll i = 2;i <= n;i++) have[1][i] += have[1][i - 1];

    for (ll i = n - 1;i > 0;i--) have[0][i] += have[0][i + 1];

    for (ll i = n - 1;i > 0;i--) have[0][i] += have[0][i + 1];
    //for (ll i = 1;i <= n;i++) cout<<have[0][i]<<" "; return 0;

    for (ll i = 1;i <= n;i++){
        ll kq = have[0][i + 1] + have[1][i - 1],mx = 0;
        for (ll j = 0;j < 26;j++) mx = max(mx,creat[i][j]);
        ans = max(ans,kq + mx + 1 + got[i]); //cout<<i<<" "<<kq + mx<<"\n";
    }
    cout<<ans;
}
/// be confident

Compilation message

palinilap.cpp: In function 'int main()':
palinilap.cpp:36:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   36 |         freopen(task".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
palinilap.cpp:37:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   37 |         freopen(task".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 332 KB Output is correct
3 Correct 1 ms 340 KB Output is correct
4 Correct 1 ms 340 KB Output is correct
5 Correct 1 ms 340 KB Output is correct

Subtask #2
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 1632 KB Output is correct
2 Correct 2 ms 1620 KB Output is correct
3 Correct 3 ms 1616 KB Output is correct
4 Correct 2 ms 1108 KB Output is correct
5 Correct 3 ms 1364 KB Output is correct
6 Correct 3 ms 1620 KB Output is correct
7 Correct 3 ms 1620 KB Output is correct

Subtask #3
46.0 / 46.0

# Verdict Execution time Memory Grader output
1 Correct 53 ms 25680 KB Output is correct
2 Correct 40 ms 25732 KB Output is correct
3 Correct 45 ms 25764 KB Output is correct
4 Correct 63 ms 25724 KB Output is correct
5 Correct 58 ms 25908 KB Output is correct
6 Correct 51 ms 25688 KB Output is correct
7 Correct 56 ms 25672 KB Output is correct
8 Correct 26 ms 5340 KB Output is correct
9 Correct 61 ms 25704 KB Output is correct
10 Correct 55 ms 25676 KB Output is correct
11 Correct 41 ms 25684 KB Output is correct
12 Correct 66 ms 25740 KB Output is correct
13 Correct 61 ms 25660 KB Output is correct
14 Correct 54 ms 25680 KB Output is correct
15 Correct 58 ms 25740 KB Output is correct
16 Correct 49 ms 25656 KB Output is correct
17 Correct 51 ms 25688 KB Output is correct
18 Correct 54 ms 25700 KB Output is correct
19 Correct 52 ms 25676 KB Output is correct