Submission #1002808

#	Time	Username	Problem	Language	Result	Execution time	Memory
1002808		Cadoc	Difference (POI11_roz)	C++14	100 / 100	624 ms	21072 KiB

roz

/*
    Author: Cadocx
    Codeforces: https://codeforces.com/profile/Kadoc
    VNOJ: oj.vnoi.info/user/Cadoc
*/

#include <bits/stdc++.h>
using namespace std;

// input/output
#define fastIO ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define el cout << '\n'
#define execute cerr << "Time elapsed: " << (1.0 * clock() / CLOCKS_PER_SEC) << "s"
// #pragma GCC optimize("O2", "unroll-loops", "Ofast")
// #pragma GCC target("avx,avx2,fma")
//data type
#define int128 __uint128_t
#define ll long long
#define ull unsigned long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define piv pair<int, vector<int>>
#define vi vector<int>
#define vl vector<ll>
#define vc vector<char>
//STL
#define sz(x) (int)(x).size()
#define for1(i,l,r) for(auto i = l; i <= r; i++)
#define for2(i,r,l) for(auto i = r; i >= l; i--)
#define forin(i,a) for(auto i : a)
#define pb push_back
#define eb emplace_back
#define pf push_front
#define all(x) (x).begin(), (x).end()
#define fi first
#define se second
//bitmask
#define bitcnt(n) __builtin_popcount(n)
#define mask(i) (1 << (i))
#define bit(n, i) (((n) >> (i)) & 1)
#define set_on(n, i) ((n) | mask(i))
#define set_off(n, i) ((n) & ~mask(i))
//constant
#define N 1000005
#define MOD 1000230007
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define base 31
#define Kadoc 0

int n;
vector<int> pos[32];
ll ans = 0, Min[N];

void calc(int x, int y){
    if(x == y || !pos[x].size() || !pos[y].size()) return;

    vector<int> a; a.pb(0);
    for(int i=0, j=0; i<sz(pos[x]) || j<sz(pos[y]);){
        if(j == sz(pos[y]) || (i < sz(pos[x]) && pos[x][i] <= pos[y][j])){
            a.pb(1);
            i++;
        }
        else{
            a.pb(-1);
            j++;
        }
    }

    int last = -1, m = sz(a)-1;
    ll s = 0;
    for(int i=1; i<=m; ++i){
        s += a[i];
        Min[i] = min(Min[i-1], s);
        if(a[i] == -1) last = i;
        if(last != -1) ans = max(ans, s - Min[last-1]);
    }
}

void solve(){
    cin >> n;
    for(int i=1; i<=n; ++i){
        char x; cin >> x;
        pos[x-'a'+1].pb(i);
    }

    for(int i=1; i<=26; ++i) for(int j=1; j<=26; ++j) calc(i, j);

    cout << ans;
}

int main(){
    #define NAME "TASK"
    if(fopen(NAME".inp", "r")){
        freopen(NAME".inp", "r", stdin);
        freopen(NAME".out", "w", stdout);
    }

    fastIO;
    
    if(Kadoc){
        int tc; cin >> tc;
        while(tc--){
            solve();
        }
    } else solve();
}

Compilation message (stderr)

roz.cpp: In function 'int main()':
roz.cpp:95:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   95 |         freopen(NAME".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
roz.cpp:96:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   96 |         freopen(NAME".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 10 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10
• Subtask 8: 10 / 10
• Subtask 9: 10 / 10
• Subtask 10: 10 / 10