Submission #888589

#	Time	Username	Problem	Language	Result	Execution time	Memory
888589		yfrank792	Election (BOI18_election)	C++14	0 / 100	4 ms	4444 KiB

election

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

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef queue<int> qi;
typedef set<int> si;

typedef priority_queue<int> pqi;
typedef priority_queue<ll> pql;
typedef priority_queue<int,vi,greater<int> > pqi_g;
typedef priority_queue<ll,vll,greater<ll> > pql_g;

#define F first
#define S second
#define PB push_back
#define PF push_front
#define MP make_pair
#define FOR(i,a,b) for (int i=a; i<=b; i++)
#define _FOR(i,a,b) for (int i=a; i>=b; i--)
#define F0R(i,a,b,x) for (int i=a; i<=b; i+=x)
#define FOR_(x,v) for (auto x : v)
#define F0R_(x,v) for (auto &x : v)

const int INF = 0x3f3f3f3f;
const int maxn = 5e5+5;
const ll MOD = 1e9+7;

//? link: https://oj.uz/problem/view/BOI18_election

//? sol: 

int n, q;

class segtree {
    ll d[4*maxn];
    private:
        ll inline ls(ll x) {return x<<1;}
        ll inline rs(ll x) {return x<<1|1;}
        ll inline op(ll u,ll v) {return min(u,v);}       // good for generalization
    public:
        ll a[maxn];
        void init(ll s=1,ll t=n,ll p=1) {
            if (s==t) {
                d[p] = a[s];
                return;
            }
            ll mid = s + ((t-s)>>1);
            init(s, mid, ls(p));
            init(mid+1, t, rs(p));
            d[p] = op(d[ls(p)], d[rs(p)]);
        }
        ll query(ll l,ll r,ll s=1,ll t=n,ll p=1) {      // query(l,r)
            if (l<=s && t<=r) return d[p]; 
            ll mid = s + ((t-s)>>1), cnt=0;
            if (l<=mid) cnt=op(cnt, query(l,r,s,mid,ls(p)));
            if (r>mid) cnt=op(cnt, query(l,r,mid+1,t,rs(p)));
            return cnt;
        }
        void upd(ll v,ll x,ll s=1,ll t=n,ll p=1) {      // upd pos v into value x ~ p=cur pos, s,t=cur range
            if (s==t) {
                d[p] = x;
                return;
            }
            ll mid = s + ((t-s)>>1);
            if (v<=mid) upd(v,x,s,mid,ls(p));
            else upd(v,x,mid+1,t,rs(p));
            d[p] = op(d[ls(p)], d[rs(p)]);
        }
} pre, suf;

int a[maxn];

int main()
{
    // faster cin/cout
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    // freopen("c.in","r",stdin);

    cin >> n;
    FOR(i,1,n) {
        char c; cin>>c;
        a[i] = (c=='C'? 1:-1);
    }
    FOR(i,1,n) pre.a[i]=pre.a[i-1]+a[i];
    _FOR(i,n,1) suf.a[i]=suf.a[i+1]+a[i];
    pre.init();
    suf.init();

    cin >> q;
    FOR(_,1,q) {
        int l,r; cin>>l>>r;
        int pr = 0-min((pre.query(l,r)-pre.a[l-1]-1)/2,(ll)0);
        int sf = 0-min((suf.query(l,r)-suf.a[r+1]-1)/2,(ll)0);
        cout << pr+sf << endl;
    }

    return 0;   
}

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