Submission #789732

#	Time	Username	Problem	Language	Result	Execution time	Memory
789732		bLIC	Necklace (Subtask 4) (BOI19_necklace4)	C++17	15 / 15	203 ms	396 KiB

necklace

/**
 *  Author: Anil Byar
**/
 
#include <bits/stdc++.h>
// #include <ext/pb_ds/assoc_container.hpp>
// #include <ext/pb_ds/tree_policy.hpp>
 
// using namespace __gnu_pbds;
using namespace std;
 
// template<class T>
// using ordered_set = tree<T, null_type, less_equal<T>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
 
 
 
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define sz(x) (int)(x).size()
#define uniq(v) v.erase(unique(all(v)), v.end())
#define ft first
#define sd second
#define pb push_back
#define eb emplace_back
 
// Source: https://codeforces.com/blog/entry/68809
// { start
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}
 
template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
// } end
 
 
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<pii> vii;
typedef vector<ll> vl;
typedef vector<pll> vll;
typedef vector<vi> vvi;
typedef vector<vii> vvii;
typedef vector<vl> vvl;
 
#define dbg if(0)
 
const ll MOD = 1e9+7;
const ll MOD9 = 998244353;
const ll INFLL = 1e18+5;
const int INF = 1e9;
 
void printbit(int x, int len) {string s="\n";while(len--){s=((x%2)?'1':'0')+s;x/=2;} cout<<s;}
ll power(ll x, ll y, ll mod){if (y==0) return 1;ll ret = power(x, y/2, mod);ret *= ret;ret%=mod;if (y&1) ret *= x;return ret%mod;}
ll modinv(ll x, ll mod = MOD) {return power(x, mod-2, mod);}
 
template<class T> bool chmin(T& a, T b){return (a>b?a=b,1:0);}
template<class T> bool chmax(T& a, T b){return (a<b?a=b,1:0);}
template<class T>
istream& operator>>(istream&in, vector<T>&v){
    for (T& x:v) in>>x;
    return in;
}
template<class T>
ostream& operator<<(ostream&out, vector<T>&v){
    for (T& x:v) out<<x<<' ';
    cout<<'\n';
    return out;
}
// use ?: with brackets (?:)
// check for overflow
// think about dp
// Read the statement carefully
 
// abcd
// cdab....
 
// ab....ab|cd
// cd....ab|cd


vector<int> KMP(const string &s, const string& t) {
	int n = (int)s.size();
	vector<int> pi_s(n);
	for (int i = 1, j = 0; i < n; i++) {
		while (j > 0 && s[j] != s[i]) { j = pi_s[j - 1]; }
		if (s[i] == s[j]) { j++; }
		pi_s[i] = j;
	}
 
    n = sz(t);
    vi ans(n);
    for (int i = 0, j = 0; i < n; i++){
        while(j>0 && s[j]!=t[i]) j = pi_s[j-1];
        if (s[j]==t[i]) j++;
        ans[i] = j;
    }
	return ans;
}


void solve(){
    string s, t;cin>>s>>t;
    int st1, st2, ans = -1;

    for (int xx = 0;xx<2;xx++){
        for (int j = 0;j<sz(t);j++){
            string right = t.substr(j);
            string left = t.substr(0, j);


            vi rightKmp = KMP(right, s);

            reverse(all(left));
            reverse(all(s));
            vi leftKmp = KMP(left, s);
            reverse(all(s));
            reverse(all(leftKmp));

            for (int i = 0;i<sz(s);i++){
                int tmp = 0;
                if (i<sz(s)-1) tmp += leftKmp[i+1];
                tmp += rightKmp[i];
                if (chmax(ans, tmp)){
                    st1 = i - rightKmp[i] + 1;
                    st2 = j;
                    if (i<sz(s) - 1) st2 -= leftKmp[i+1];
                    if (xx==1) st2 = sz(t) - st2 - ans;
                }
            }
        }
        reverse(all(t));
    }
    assert(ans>0);
    cout<<ans<<'\n'<<st1<<" "<<st2;
}
 
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
 
 
    solve();

}

Compilation message (stderr)

necklace.cpp: In function 'void solve()':
necklace.cpp:157:32: warning: 'st2' may be used uninitialized in this function [-Wmaybe-uninitialized]
  157 |     cout<<ans<<'\n'<<st1<<" "<<st2;
      |                                ^~~
necklace.cpp:157:27: warning: 'st1' may be used uninitialized in this function [-Wmaybe-uninitialized]
  157 |     cout<<ans<<'\n'<<st1<<" "<<st2;
      |                           ^~~

• Subtask 1: 15 / 15