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Submission #71718

# Submission time Handle Problem Language Result Execution time Memory
71718 2018-08-25T13:19:39 Z evpipis Palindromes (APIO14_palindrome) C++11
73 / 100
 1000 ms 25216 KB 
#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef pair<int, int> ii;

const int len = 3e5+5, mod = 1e9+7, base = 57;
int suf[len], has1[len], has2[len], po[len], lim[len], n, lef[len], rig[len];
char str[len];
vector<int> vec[len];
vector<ii> st;
set<int> mys;

int add(int a, int b){
    return (a+b)%mod;
}

int sub(int a, int b){
    return (mod+a-b)%mod;
}

int mul(int a, int b){
    return (a*1LL*b)%mod;
}

int val1(int l, int r){
    l++, r++;
    return sub(has1[r], mul(has1[l-1], po[r-l+1]));
}

int val2(int l, int r){
    return (sub(has2[l], mul(has2[r+1], po[r-l+1])));
}

int lcp(int a, int b){
    int l = 1, r = n-1-max(a, b)+1, ans = 0;
    while (l <= r){
        int mid = (l+r)/2;
        if (val1(a, a+mid-1) == val1(b, b+mid-1))
            ans = mid, l = mid+1;
        else
            r = mid-1;
    }

    return ans;
}

bool comp(int a, int b){
    int c = lcp(a, b);
    return (str[a+c] < str[b+c]);
}

int bs(int i, int t){
    int l = 1, r = min(n-i-t, i+1), ans = 0;
    while (l <= r){
        int mid = (l+r)/2;
        if (val1(i-mid+1, i+t+mid-1) == val2(i-mid+1, i+t+mid-1))
            ans = 2*mid - (1-t), l = mid+1;
        else
            r = mid-1;
    }

    return ans;
}

int main(){
    scanf("%s", &str);
    n = strlen(str);
    str[n] = 0;

    po[0] = 1;
    for (int i = 1; i <= n; i++)
        po[i] = mul(po[i-1], base);
    for (int i = 1; i <= n; i++)
        has1[i] = add(mul(has1[i-1], base), str[i-1]-'a');
    for (int i = n-1; i >= 0; i--)
        has2[i] = add(mul(has2[i+1], base), str[i]-'a');

    for (int i = 0; i < n; i++)
        suf[i] = i;
    sort(suf, suf+n, comp);

    for (int i = 0; i < n; i++)
        lim[i] = -1;
    for (int i = 0; i < n-1; i++)
        lim[suf[i]] = lcp(suf[i], suf[i+1]);

    //for (int i = 0; i < n; i++)
      //  printf("%d ", suf[i]);
    //printf("\n");

    ll ans = 0;
    for (int i = 0; i < n; i++){
        int temp = bs(i, 0);
        vec[i-temp/2].pb(temp);
        ans = max(ans, (ll)temp);

        //printf("i = %d, mx0 = %d\n", i, temp);

        temp = bs(i, 1);
        vec[i-temp/2+1].pb(temp);
        ans = max(ans, (ll)temp);

        //printf("i = %d, mx1 = %d\n", i, temp);
    }

    int k = 0;
    for (int i = 0; i < n; i++){
        for (int j = 0; j < vec[i].size(); j++)
            mys.insert(vec[i][j]-k);

        set<int>::iterator it = mys.upper_bound(lim[i]-k);
        if (lim[i] != -1 && it != mys.begin()){
            it = prev(it);
            lim[i] = *it + k;
        }
        else
            lim[i] = 0;

        k-=2;
    }

    //for (int i = 0; i < n-1; i++)
      //  printf("%d ", lim[suf[i]]);
    //printf("\n");

    st.pb(mp(-1, -1));
    for (int i = 0; i < n-1; i++){
        while (lim[suf[i]] <= st.back().fi)
            st.pop_back();
        lef[i] = st.back().se;
        st.pb(mp(lim[suf[i]], i));
    }

    st.clear(), st.pb(mp(-1, n-1));
    for (int i = n-2; i >= 0; i--){
        while (lim[suf[i]] <= st.back().fi)
            st.pop_back();
        rig[i] = st.back().se;
        st.pb(mp(lim[suf[i]], i));
    }

    for (int i = 0; i < n-1; i++)
        ans = max(ans, lim[suf[i]] * 1LL * (rig[i]-lef[i]));
    printf("%lld\n", ans);
    return 0;
}

Compilation message

palindrome.cpp: In function 'int main()':
palindrome.cpp:71:21: warning: format '%s' expects argument of type 'char*', but argument 2 has type 'char (*)[300005]' [-Wformat=]
     scanf("%s", &str);
                 ~~~~^
palindrome.cpp:113:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < vec[i].size(); j++)
                         ~~^~~~~~~~~~~~~~~
palindrome.cpp:71:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s", &str);
     ~~~~~^~~~~~~~~~~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 7416 KB Output is correct
2 Correct 9 ms 7596 KB Output is correct
3 Correct 11 ms 7596 KB Output is correct
4 Correct 10 ms 7596 KB Output is correct
5 Correct 9 ms 7596 KB Output is correct
6 Correct 11 ms 7596 KB Output is correct
7 Correct 9 ms 7596 KB Output is correct
8 Correct 10 ms 7596 KB Output is correct
9 Correct 9 ms 7716 KB Output is correct
10 Correct 9 ms 7716 KB Output is correct
11 Correct 9 ms 7716 KB Output is correct
12 Correct 9 ms 7716 KB Output is correct
13 Correct 8 ms 7716 KB Output is correct
14 Correct 10 ms 7716 KB Output is correct
15 Correct 9 ms 7780 KB Output is correct
16 Correct 7 ms 7780 KB Output is correct
17 Correct 12 ms 7780 KB Output is correct
18 Correct 9 ms 7780 KB Output is correct
19 Correct 10 ms 7780 KB Output is correct
20 Correct 10 ms 7780 KB Output is correct
21 Correct 10 ms 7780 KB Output is correct
22 Correct 10 ms 7784 KB Output is correct
23 Correct 11 ms 7792 KB Output is correct
24 Correct 9 ms 7856 KB Output is correct
25 Correct 8 ms 7856 KB Output is correct
26 Correct 8 ms 7856 KB Output is correct
27 Correct 11 ms 7856 KB Output is correct
28 Correct 10 ms 7856 KB Output is correct
29 Correct 8 ms 7856 KB Output is correct
30 Correct 9 ms 7876 KB Output is correct
31 Correct 8 ms 7880 KB Output is correct
32 Correct 9 ms 7884 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 8016 KB Output is correct
2 Correct 11 ms 8020 KB Output is correct
3 Correct 12 ms 8024 KB Output is correct
4 Correct 11 ms 8028 KB Output is correct
5 Correct 10 ms 8032 KB Output is correct
6 Correct 10 ms 8036 KB Output is correct
7 Correct 12 ms 8040 KB Output is correct
8 Correct 12 ms 8044 KB Output is correct
9 Correct 10 ms 8048 KB Output is correct
10 Correct 12 ms 8052 KB Output is correct
11 Correct 12 ms 8056 KB Output is correct
12 Correct 12 ms 8132 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 47 ms 9620 KB Output is correct
2 Correct 51 ms 9628 KB Output is correct
3 Correct 42 ms 9740 KB Output is correct
4 Correct 72 ms 9924 KB Output is correct
5 Correct 56 ms 9924 KB Output is correct
6 Correct 54 ms 9924 KB Output is correct
7 Correct 51 ms 9924 KB Output is correct
8 Correct 48 ms 9924 KB Output is correct
9 Correct 48 ms 9924 KB Output is correct
10 Correct 79 ms 9924 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 601 ms 24640 KB Output is correct
2 Correct 669 ms 24640 KB Output is correct
3 Correct 530 ms 25216 KB Output is correct
4 Correct 996 ms 25216 KB Output is correct
5 Correct 695 ms 25216 KB Output is correct
6 Correct 649 ms 25216 KB Output is correct
7 Correct 749 ms 25216 KB Output is correct
8 Correct 725 ms 25216 KB Output is correct
9 Correct 650 ms 25216 KB Output is correct
10 Correct 769 ms 25216 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1059 ms 25216 KB Time limit exceeded
2 Halted 0 ms 0 KB -