Submission #1279829

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279829		mactoddlover	Sum Zero (RMI20_sumzero)	C++17	61 / 100	288 ms	53316 KiB

sumzero

#include<bits/stdc++.h>

#define MASK(i) (1 << (i))
#define pub push_back
#define all(v) v.begin(), v.end()
#define compact(v) v.erase(unique(all(v)), end(v))
#define pii pair<int,int>
#define fi first
#define se second
#define endl "\n"
#define sz(v) (int)(v).size()
#define dbg(x) "[" #x " = " << (x) << "]"
#define vi vector<int>

using namespace std;

template<class T> bool minimize(T& a, T b){if(a > b) return a = b, true;return false;}
template<class T> bool maximize(T& a, T b){if(a < b) return a = b, true;return false;}

typedef long long ll;
typedef long double ld;

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rand(ll l, ll r){return uniform_int_distribution<ll>(l, r)(rng);}

const int MAX = 4e5 + 15;

int n, q;
int a[MAX];
int qL[MAX], qR[MAX];
ll pref[MAX];
int lst[MAX];

namespace subtask1{
    bool check(void){
        return max(n, q) <= 5000;
    }

    int dp[5005];

    int calc(int l, int r){
        fill(dp + 1, dp + 1 + n, 0);
        for(int i = l; i <= r; i++){
            dp[i] = dp[i-1];
            if(lst[i] >= l) maximize(dp[i], dp[lst[i]-1] + 1);
        }
        return dp[r];
    }

    void main(){
        fill(lst + 1, lst + 1 + n, -1);

        for(int i = 1; i <= n; i++){
            for(int j = i-1; j >= 0; j--) if(pref[i] == pref[j]){
                lst[i] = j+1;
                break;
            }
        }

        for(int i = 1; i <= q; i++){
            cout << calc(qL[i], qR[i]) << endl;
        }
    }
}

namespace subtask3{
    map<ll, int> mp;
    int nearest[MAX];
    int spt[MAX][19];

    void main(){
        fill(lst + 1, lst + 1 + n, -1);

        mp[0] = 1;

        for(int i = 1; i <= n; i++){
            if(mp.count(pref[i])) lst[i] = mp[pref[i]];
            mp[pref[i]] = i+1;
        }

        for(int i = 1, maL = 0; i <= n; i++) if(lst[i]){
            if(maL >= lst[i]) lst[i] = 0;
            else maximize(maL, lst[i]);
            nearest[i] = maL;
        }

        for(int i = 1; i <= n; i++) if(lst[i]){
            spt[lst[i]][0] = nearest[lst[i]-1];
        }

        int lg = 31 - __builtin_clz(n);

        for(int j = 1; j <= lg; j++){
            for(int i = n; i - (1 << j) + 1 > 0 ; i--){
                spt[i][j] = spt[spt[i][j-1]][j-1];
            }
        }

        for(int i = 1; i <= q; i++){
            int l, r; tie(l, r) = {qL[i], qR[i]};
            int jump = nearest[r];
            int answer = (nearest[r] >= l);
            for(int j = 31 - __builtin_clz(r - l + 1); j >= 0; j--){
                if(spt[jump][j] >= l){
                    jump = spt[jump][j];
                    answer += (1 << j);
                }
            }
            cout << answer << endl;
        }
    }
}

void solve(){
    cin >> n;

    for(int i = 1; i <= n; i++){
        cin >> a[i];
        pref[i] = pref[i-1] + a[i];
    }

    cin >> q;

    for(int i = 1; i <= q; i++){
        cin >> qL[i] >> qR[i];
    }

    if(subtask1::check()) subtask1::main();
    else subtask3::main();
}

signed main(){
    ios_base::sync_with_stdio(NULL);
    cin.tie(0); cout.tie(0);

    #define task "task"

    if(fopen(task".INP", "r")){
        freopen(task".INP", "r", stdin);
        freopen(task".OUT", "w", stdout);
    }

    int t; t = 1; //cin >> t;
    while(t--) solve();
}

Compilation message (stderr)

sumzero.cpp: In function 'int main()':
sumzero.cpp:139:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  139 |         freopen(task".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
sumzero.cpp:140:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  140 |         freopen(task".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 39 / 39
• Subtask 3: 0 / 39