Submission #800266

#	Time	Username	Problem	Language	Result	Execution time	Memory
800266		GrindMachine	Necklace (Subtask 1-3) (BOI19_necklace1)	C++17	85 / 85	227 ms	106396 KiB

necklace

// Om Namah Shivaya

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x, y) ((x + y - 1) / (y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i, n) for(int i = 0; i < n; ++i)
#define rep1(i, n) for(int i = 1; i <= n; ++i)
#define rev(i, s, e) for(int i = s; i >= e; --i)
#define trav(i, a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a, b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a, b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
edi

*/

const int MOD = 1e9 + 7;
const int N = 3e3 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

int lss[N][N], lsp[N][N], lps[N][N];

void solve(int test_case)
{
    string s,t; cin >> s >> t;
    int n = sz(s), m = sz(t);
    s = "$" + s;
    t = "$" + t;

    auto go = [&]() -> array<int,3> {
        memset(lss,0,sizeof lss);
        memset(lsp,0,sizeof lsp);
        memset(lps,0,sizeof lps);

        rep1(i,n){
            rep1(j,m){
                if(s[i] == t[j]){
                    lss[i][j] = 1 + lss[i-1][j-1];
                }
            }
        }

        rep1(i,n){
            rep1(j,m){
                int l = lss[i][j];
                amax(lsp[i][j-l+1],l);
                amax(lps[i-l+1][j],l);
            }
        }

        rep1(i,n){
            rep1(j,m){
                amax(lsp[i][j],lsp[i][j-1]-1);
                amax(lps[i][j],lps[i-1][j]-1);
            }
        }

        /*

        rep1(i,n){
            rep1(j,m){
                int l = lss[i][j];
                for(int k = j-l+1; k <= j; ++k){
                    amax(lsp[i][k],j-k+1);
                }
                for(int k = i-l+1; k <= i; ++k){
                    amax(lps[k][j],i-k+1);
                }
            }
        }
    
        */

        array<int,3> res;
        res.fill(-1);

        rep1(i,n){
            rep1(j,m){
                int l1 = lsp[i][j];
                int l2 = lps[i+1][j-1];
                int len = l1+l2;
                array<int,3> curr = {len,i-l1,j-l2-1};
                amax(res,curr);
            }
        }

        return res;
    };

    auto ans1 = go();
    reverse(t.begin()+1,t.end());
    auto ans2 = go();

    ans2[2] = m-1-ans2[2];
    ans2[2] -= ans2[0];
    ans2[2]++;

    auto ans = max(ans1,ans2);

    cout << ans[0] << endl;
    cout << ans[1] << " " << ans[2] << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 25 / 25
• Subtask 2: 20 / 20
• Subtask 3: 40 / 40