Submission #1079036

#	Time	Username	Problem	Language	Result	Execution time	Memory
1079036		steveonalex	Election (BOI18_election)	C++17	100 / 100	862 ms	102068 KiB

election

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1LL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
#define block_of_code if(true)
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ll mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

struct FenwickTree{
    int n;
    vector<int> a;

    FenwickTree(int _n){
        n = _n;
        a.resize(n+1);
    }

    void update(int i, int v){
        while(i <= n){
            a[i] += v;
            i += LASTBIT(i);
        }
    }

    int get(int i){
        int ans = 0;
        while(i > 0){
            ans += a[i];
            i -= LASTBIT(i);
        }
        return ans;
    }

    int get(int l, int r){return get(r) - get(l-1);}
};

struct SegmentTree{
    int n;
    vector<int> a, lazy;
    SegmentTree(int _n){
        n = _n;
        a.resize(n * 4 + 4); lazy.resize(n * 4 + 4);
    }

    void down(int id){
        #define push(x) {lazy[x] += lazy[id]; a[x] += lazy[id];}
        push(id * 2); push(id * 2 + 1);
        lazy[id] = 0;
    }

    void update(int u, int v, int val, int l, int r, int id){
        if (u <= l && r <= v){
            a[id] += val;
            lazy[id] += val;
            return;
        }
        if (lazy[id]) down(id);
        int mid = (l + r) >> 1;
        if (u <= mid) update(u, v, val, l, mid, id * 2);
        if (v > mid) update(u, v, val, mid + 1, r, id * 2 + 1);
        a[id] = min(a[id * 2], a[id * 2 + 1]);
    }

    void update(int u, int v, int val){
        update(u, v, val, 1, n, 1);
    }

    int get(int u, int v, int l, int r, int id){
        if (u <= l && r <= v) return a[id];
        if (lazy[id]) down(id);
        int mid = (l + r) >> 1;
        int ans = 1e9;
        if (u <= mid) minimize(ans, get(u, v, l, mid, id * 2));
        if (v > mid) minimize(ans, get(u, v, mid + 1, r, id * 2 + 1));
        return ans;
    }

    int get(int u, int v){return get(u, v, 1, n, 1);}
};

const int N = 5e5 + 69;
vector<int> graph[N];
vector<pair<int, int>> queries[N];
int ans[N];

void dfs(int u, FenwickTree &bit, SegmentTree &st){
    if (u) {
        bit.update(u, 1);
        st.update(1, u, 1);
    }
    for(pair<int, int> j: queries[u+1]){
        int idx = j.second, r = j.first;
        ans[idx] = bit.get(u + 1, r) + (st.get(r + 1, r + 1) - st.get(u + 1, r + 1));
    }
    for(int v: graph[u]) dfs(v, bit, st);
    if (u) {
        bit.update(u, -1);
        st.update(1, u, -1);
    }
}

int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    clock_t start = clock();

    int n; cin >> n;
    string s; cin >> s;
    s = "#" + s;

    vector<int> a(n+1);
    for(int i= 1; i<=n; ++i){
        a[i] = a[i-1];
        if (s[i] == 'C') a[i]++;
        else a[i]--;
    }

    vector<int> st;
    vector<int> nxt(n+1, n+1);
    for(int i = n; i>=0; --i){
        while(st.size() && a[st.back()] >= a[i]) st.pop_back();
        if (st.size()) nxt[i] = st.back();
        st.push_back(i);
    }

    for(int i = 0; i<=n; ++i) graph[nxt[i]].push_back(i);

    int q; cin >> q;
    for(int i = 1; i<=q; ++i) {
        int l, r; cin >> l >> r;
        queries[l].push_back({r, i});
    }

    vector<int> b(n+2);
    for(int i = n; i>=1; --i){
        b[i] = b[i+1];
        if (s[i] == 'C') b[i]++;
        else b[i]--;
    }

    FenwickTree bit(n);
    SegmentTree segg(n+1);
    for(int i = 1; i<=n+1; ++i) segg.update(i, i, b[i]);
    dfs(n+1, bit, segg);
    
    for(int i = 1; i<=q; ++i) 
        cout << ans[i] << " "; 
    cout << "\n";


    cerr << "Time elapsed: " << clock() - start << " ms\n";
    return 0;
}

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