Submission #1208841

#	Time	Username	Problem	Language	Result	Execution time	Memory
1208841		goulthen	Election (BOI18_election)	C++20	0 / 100	14 ms	19008 KiB

election

//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <class T>
using Tree =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
#define int long long
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define rep(i, a, b) for (int i = a; i <= b; ++i)
#define per(i, b, a) for (int i = b; i >= a; --i)
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()
#define lsb(x) (x)&(-x)
 
void setIO(string name = "") {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);cout.tie(nullptr);
    if (!name.empty()) {
        freopen((name + ".in").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}
 
ll fexp(ll a, ll b, ll m) {
    if (b == 0) return 1LL;
    ll p = a;
    ll ans = 1;
 
    while (b > 0) {
        if (b % 2 != 0) ans = (ans*p)%m;
        p = (p*p)%m;
        b >>= 1;
    }
    return ans;
}
 
const int MAXN = 2e5+10;
const int INF = 1e18 + 5;
const int MOD = 1e9+7;
int a[MAXN];

struct Node {
int s=0,pfx=INF,sfx=INF;
};
 
struct Seg3 {
    Node seg3[4*MAXN];
    Node join(Node x, Node y) {
        Node r;
        r.s = x.s + y.s;
        r.pfx = min(x.pfx,y.pfx+x.s);
        r.sfx = min(x.sfx + y.s,y.sfx);
        return r;
    }
 
    void build(int i, int l, int r) {
        if (l == r) {
            seg3[i] = {a[l],a[l],a[l]};
            return;
        }
        int mid =(l+r)>>1;
        build(2*i,l,mid);
        build(2*i+1,mid+1,r);
        seg3[i] = join(seg3[2*i],seg3[2*i+1]);
    }
 
    Seg3(int l, int r) {
        build(1,l,r);
    }
    void update(int i, int l, int r, int ti, int x) {
        if (ti < l || ti > r) return;
        if (l==r) {
            seg3[i] = {x,x,x};
            return;
        }
        int mid =(l+r)>>1;
        update(2*i,l,mid,ti,x);
        update(2*i+1,mid+1,r,ti,x);
        seg3[i] = join(seg3[2*i],seg3[2*i+1]);
    }
    Node query(int i, int l, int r, int tl, int tr) {
        if (tr < l || tl > r) return {0,INF,INF};
        if (l >= tl && r <= tr) return seg3[i];
        int mid =(l+r)>>1;
        return join(query(2*i,l,mid,tl,tr),query(2*i+1,mid+1,r,tl,tr));
    }
};

void solve() {
    string s;
    int n,q;cin >> n >> s;
    rep(i,1,n) a[i] = (s[i-1]=='C'?1:-1);
    cin >> q;
    Seg3 seg(1,n);
    while (q--) {
        int l,r;cin >> l >> r;
        cout << max(-seg.query(1,1,n,l,r).pfx, -seg.query(1,1,n,l,r).sfx) << '\n';
    }
}

 
int32_t main() {
    setIO();
    int tt = 1;
    //cin >> tt;
 
    while (tt-- > 0) solve();
}

Compilation message (stderr)

election.cpp: In function 'void setIO(std::string)':
election.cpp:28:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   28 |         freopen((name + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:29:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 28
• Subtask 2: 0 / 54
• Subtask 3: 0 / 18