oj.uz

Submission #308042

# Submission time Handle Problem Language Result Execution time Memory
308042 2020-09-30T00:38:29 Z Elephant52 Palindromes (APIO14_palindrome) C++11
73 / 100
 138 ms 129468 KB 
#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<pair<int, int> > vpi;

#define INF 1000000000
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define rep(i,a,b) for (int i = a; i < b; i++)

void setIO(string name) {
    freopen((name+".in").c_str(), "r", stdin); 
    freopen((name+".out").c_str(), "w", stdout);
}

string s;

typedef struct node {
    int next[26];
    ll len = 0, suflink = 0, num = 0;
    node() {};
} node;

node tree[300001];
int num, suf;
vi adj[300001];

bool add_letter(int pos) { //return 1 on new palindromes
    int cur = suf, letter = (s[pos]-'a'), curlen = 0;
    
    while(1) { //find longest palindromic suffix of s[0...pos-1] that can include s[pos]
        curlen = tree[cur].len;
        if (pos > curlen && s[pos-1-curlen] == s[pos]) break;
        cur = tree[cur].suflink;
    }
    
    if (tree[cur].next[letter]) { //if there exists a link from smaller palindrome to s[pos] + pal + s[pos] then do nothing
        suf = tree[cur].next[letter];
        tree[suf].num++;
        return 0;
    }
    
    //create a new palindrome with id num+1 in the tree
    
    suf = ++num;
    tree[num].num = 1;
    tree[num].len = tree[cur].len + 2; //add on s[pos]
    tree[cur].next[letter] = num;
    
    if (tree[num].len == 1) {
        tree[num].suflink = 2; //link to the empty palindrome
        adj[2].PB(num);
        return 1;
    } 
    
    while(1) {
        cur = tree[cur].suflink;
        curlen = tree[cur].len;
        if (pos > curlen && s[pos-1-curlen] == s[pos]) {
            tree[num].suflink = tree[cur].next[letter];
            adj[tree[cur].next[letter]].PB(num);
            break;
        }
    }
    
    return 1;
}



void dfs(int cur = 1, int par = -1) {
    for (auto edge : adj[cur]) {
        if (edge != par) {
            dfs(edge, cur);
            tree[cur].num += tree[edge].num;
        }
    }
}

void init() {
    num = suf = 2;
    tree[1].len = -1, tree[2].len = 0;
    tree[1].suflink = tree[2].suflink = 1;
    adj[1].PB(2);
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);

    cin >> s;
    
    init();
    
    rep(i,0,s.length()) add_letter(i);
    
    ll ans = 0;
    
    dfs();
    
    rep(i,1,300001) ans = max(ans, tree[i].len * tree[i].num);
    
    cout << ans << endl;

    return 0;
}

Compilation message

palindrome.cpp: In function 'int main()':
palindrome.cpp:15:38: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 | #define rep(i,a,b) for (int i = a; i < b; i++)
......
  100 |     rep(i,0,s.length()) add_letter(i);
      |         ~~~~~~~~~~~~~~                
palindrome.cpp:100:5: note: in expansion of macro 'rep'
  100 |     rep(i,0,s.length()) add_letter(i);
      |     ^~~
palindrome.cpp: In function 'void setIO(std::string)':
palindrome.cpp:18:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   18 |     freopen((name+".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
palindrome.cpp:19:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   19 |     freopen((name+".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 44928 KB Output is correct
2 Correct 25 ms 44928 KB Output is correct
3 Correct 24 ms 44928 KB Output is correct
4 Correct 24 ms 44928 KB Output is correct
5 Correct 24 ms 44920 KB Output is correct
6 Correct 29 ms 44928 KB Output is correct
7 Correct 25 ms 44928 KB Output is correct
8 Correct 24 ms 44920 KB Output is correct
9 Correct 25 ms 44928 KB Output is correct
10 Correct 24 ms 44928 KB Output is correct
11 Correct 25 ms 44928 KB Output is correct
12 Correct 24 ms 44928 KB Output is correct
13 Correct 24 ms 44920 KB Output is correct
14 Correct 28 ms 44928 KB Output is correct
15 Correct 24 ms 44928 KB Output is correct
16 Correct 24 ms 44928 KB Output is correct
17 Correct 24 ms 44928 KB Output is correct
18 Correct 26 ms 44928 KB Output is correct
19 Correct 25 ms 44928 KB Output is correct
20 Correct 25 ms 44928 KB Output is correct
21 Correct 24 ms 44928 KB Output is correct
22 Correct 24 ms 44920 KB Output is correct
23 Correct 23 ms 44928 KB Output is correct
24 Correct 24 ms 44920 KB Output is correct
25 Correct 26 ms 45056 KB Output is correct
26 Correct 24 ms 44920 KB Output is correct
27 Correct 25 ms 44920 KB Output is correct
28 Correct 24 ms 45056 KB Output is correct
29 Correct 24 ms 44928 KB Output is correct
30 Correct 24 ms 44920 KB Output is correct
31 Correct 24 ms 44928 KB Output is correct
32 Correct 24 ms 44928 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 45056 KB Output is correct
2 Correct 24 ms 44928 KB Output is correct
3 Correct 24 ms 45056 KB Output is correct
4 Correct 25 ms 44928 KB Output is correct
5 Correct 24 ms 45056 KB Output is correct
6 Correct 24 ms 45056 KB Output is correct
7 Correct 24 ms 44928 KB Output is correct
8 Correct 25 ms 45048 KB Output is correct
9 Correct 24 ms 44928 KB Output is correct
10 Correct 24 ms 44920 KB Output is correct
11 Correct 24 ms 44928 KB Output is correct
12 Correct 24 ms 44928 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 45568 KB Output is correct
2 Correct 25 ms 45440 KB Output is correct
3 Correct 25 ms 45944 KB Output is correct
4 Correct 25 ms 45824 KB Output is correct
5 Correct 25 ms 45056 KB Output is correct
6 Correct 25 ms 45184 KB Output is correct
7 Correct 26 ms 45440 KB Output is correct
8 Correct 25 ms 44920 KB Output is correct
9 Correct 24 ms 44928 KB Output is correct
10 Correct 26 ms 45176 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 51324 KB Output is correct
2 Correct 37 ms 49912 KB Output is correct
3 Correct 39 ms 54392 KB Output is correct
4 Correct 40 ms 52216 KB Output is correct
5 Correct 38 ms 46208 KB Output is correct
6 Correct 33 ms 47224 KB Output is correct
7 Correct 34 ms 48376 KB Output is correct
8 Correct 26 ms 45184 KB Output is correct
9 Correct 28 ms 47096 KB Output is correct
10 Correct 35 ms 45944 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Runtime error 138 ms 129468 KB Execution killed with signal 11 (could be triggered by violating memory limits)
2 Halted 0 ms 0 KB -