Submission #61836

#	Time	Username	Problem	Language	Result	Execution time	Memory
61836		Benq	Election (BOI18_election)	C++11	100 / 100	1969 ms	42608 KiB

election

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i=a; i<(b); i++)
#define F0R(i, a) for (int i=0; i<(a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= a; i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)

#define sz(x) (int)(x).size()
#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define all(x) x.begin(), x.end()

const int MOD = 1000000007;
const ll INF = 1e18;
const int MX = 1<<19;


template<class T, int SZ> struct BIT {
    T bit[SZ+1];
    
    BIT() { memset(bit,0,sizeof bit); }
    
    void upd(int k, T val) { // add val to index k
        for( ;k <= SZ; k += (k&-k)) bit[k] += val;
    }
    
    T query(int k) {
        T temp = 0;
        for (;k > 0;k -= (k&-k)) temp += bit[k];
        return temp;
    }
    T query(int l, int r) { return query(r)-query(l-1); } // range query [l,r]
};

BIT<int,MX> B;

template<class T, int SZ> struct LazySegTree {
    T mx[2*SZ], lazy[2*SZ]; // set SZ to a power of 2
    
    LazySegTree() {
        memset (mx,0,sizeof mx);
        memset (lazy,0,sizeof lazy);
    }
    
    void push(int ind, int L, int R) {
        mx[ind] += lazy[ind];
        if (L != R) lazy[2*ind] += lazy[ind], lazy[2*ind+1] += lazy[ind];
        lazy[ind] = 0;
    }
    
    void pull(int ind) {
        mx[ind] = max(mx[2*ind],mx[2*ind+1]);
    }
    
    void build() {
        F0Rd(i,SZ) pull(i);
    }
    
    T query(int lo, int hi, int ind = 1, int L = 0, int R = SZ-1) {
        push(ind,L,R);
        if (lo > R || L > hi) return -MOD;
        if (lo <= L && R <= hi) return mx[ind];
        
        int M = (L+R)/2;
        return max(query(lo,hi,2*ind,L,M), query(lo,hi,2*ind+1,M+1,R));
    }
    
    void upd(int lo, int hi, ll inc, int ind = 1, int L = 0, int R = SZ-1) {
        push(ind,L,R);
        if (hi < L || R < lo) return;
        if (lo <= L && R <= hi) {
            lazy[ind] = inc;
            push(ind,L,R);
            return;
        }
        
        int M = (L+R)/2;
        upd(lo,hi,inc,2*ind,L,M); upd(lo,hi,inc,2*ind+1,M+1,R);
        pull(ind);
    }
};

LazySegTree<int,MX> L;

int N,Q,cum[MX], ans[MX];
string S;
vpi q[MX];
vpi v;

void rem() {
    B.upd(v.back().s,-1);
    L.upd(v.back().s,MX-1,-1);
    v.pop_back();
}

void ad(int x) {
    B.upd(x,1);
    L.upd(x,MX-1,1);
    v.pb({cum[x],x});
}

void solve(int x) {
    while (sz(v) && v.back().f >= cum[x]) rem();
    for (auto z: q[x]) {
        /*cout << z.s << " " << B.query(x+1,z.f) << " " << L.query(x,z.f) << " " << L.query(z.f,z.f)<< "\n";
        cout << z.f << "\n";
        for (auto a: v) cout << a.f << ' ' << a.s << " | ";
        cout << "\n";
        cout << L.query(x+1,x+1) << " " << L.query(x+2,x+2) << " " << L.query(x+3,x+3) << "\n";*/
        ans[z.s] = B.query(x+1,z.f)+L.query(x,z.f)-L.query(z.f,z.f);
    }
    if (x) ad(x);
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> N >> S >> Q;
    F0R(i,N) cum[i+1] = cum[i] + (S[i] == 'C' ? 1 : -1);
    F0R(i,N+1) L.upd(i,i,cum[i]);
    
    F0R(i,Q) {
        int L,R; cin >> L >> R;
        q[L-1].pb({R,i});
    }
    F0Rd(i,N+1) solve(i);
    F0R(i,Q) cout << ans[i] << "\n";
}

/* Look for:
* the exact constraints (multiple sets are too slow for n=10^6 :( ) 
* special cases (n=1?)
* overflow (ll vs int?)
* array bounds
*/

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