oj.uz

Submission #414216

# Submission time Handle Problem Language Result Execution time Memory
414216 2021-05-30T09:18:44 Z shivensinha4 Election (BOI18_election) C++17
100 / 100
 1624 ms 57308 KB 
#include <bits/stdc++.h>
using namespace std;
#define for_(i, s, e) for (int i = s; i < (int) e; i++)
#define for__(i, s, e) for (ll i = s; i < e; i++)
typedef long long ll;
typedef vector<int> vi;
typedef array<int, 2> ii;
//#define endl '\n'

struct Node {
    int pref = 0, sum = 0;
};

class SegmentTree {
private:
    vector<Node> tree; int n;
    Node bound = {0, 0};

    static Node merge(Node a, Node b) {
        Node ans;
        ans.sum = a.sum + b.sum;
        ans.pref = max(a.pref, a.sum + b.pref);
        return ans;
    }

    void update(int i, int val, int l, int r, int p) {
        if (l > i or r < i) return;
        if (l == r) {
            tree[p] = {val, val};
            return;
        }

        int mid = (l + r) / 2;
        int c1 = 2*p+1, c2 = 2*p+2;
        update(i, val, l, mid, c1); update(i, val, mid+1, r, c2);
        tree[p] = merge(tree[c1], tree[c2]);
    }

    Node mx(int i, int j, int l, int r, int p) {
        if (l > j or r < i) return bound;
        if (l >= i and r <= j) return tree[p];

        int mid = (l + r) / 2;
        int c1 = 2*p+1, c2 = 2*p+2;
        return merge(mx(i, j, l, mid, c1), mx(i, j, mid+1, r, c2));
    }

public:
    SegmentTree(int _n) {
        n = _n;
        tree.resize(4*n, bound);
    }

    Node mx(int i, int j) {
        return mx(i, j, 0, n-1, 0);
    }

    void update(int i, int val) {
        update(i, val, 0, n-1, 0);
    }
};

// Ask for sum 1 -> n for full (one based indexing)
class BIT {
private: vector<ll> tree; int n;
    int LSOne(int x) {
        return x&(-x);
    }

public:
    BIT(int x) {
        n = x;
        tree.resize(n+1);
    }
    ll sum(int a) {
        ll sum = 0;
        for (; a > 0; a -= LSOne(a)) sum += tree[a];
        return sum;
    }
    ll sum(int a, int b) {
        return sum(b) - (a == 1 ? 0 : sum(a-1));
    }
    void update(int p, ll v) {
        for (; p < n+1; p += LSOne(p)) tree[p] += v;
    }
};


int main() {
#ifdef mlocal
    freopen("test.in", "r", stdin);
#endif

    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int n; cin >> n;
    vi nums(n);
    for_(i, 0, n) {
        char c; cin >> c;
        nums[i] = c == 'C' ? 1 : -1;
    }


    int q; cin >> q;
    vector<vector<ii>> ends(n);
    for_(i, 0, q) {
        int l, r; cin >> l >> r;
        ends[l-1].push_back({r-1, i});
    }

    vi out(q);
    stack<int> st;

    SegmentTree tree(n);
    BIT negpref(n);

    for (int i = n-1; i >= 0; i--) {
        if (nums[i] == -1) {
            negpref.update(i+1, 1);
            st.push(i);
        }
        else {
            tree.update(i, 1);
            if (st.size()) {
                negpref.update(st.top()+1, -1);
                tree.update(st.top(), -1);
                st.pop();
            }
        }

        for (auto &r: ends[i]) {
            Node temp = tree.mx(i, r[0]);
            out[r[1]] = temp.pref - temp.sum + negpref.sum(r[0]+1);
        }

    }

    for (auto i: out) cout << i << endl;
    cout << endl;
}

Subtask #1
28.0 / 28.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 460 KB Output is correct
2 Correct 5 ms 460 KB Output is correct
3 Correct 5 ms 460 KB Output is correct
4 Correct 5 ms 460 KB Output is correct
5 Correct 7 ms 460 KB Output is correct

Subtask #2
54.0 / 54.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 460 KB Output is correct
2 Correct 5 ms 460 KB Output is correct
3 Correct 5 ms 460 KB Output is correct
4 Correct 5 ms 460 KB Output is correct
5 Correct 7 ms 460 KB Output is correct
6 Correct 197 ms 7000 KB Output is correct
7 Correct 163 ms 6596 KB Output is correct
8 Correct 169 ms 6508 KB Output is correct
9 Correct 175 ms 6848 KB Output is correct
10 Correct 171 ms 6860 KB Output is correct
11 Correct 174 ms 7060 KB Output is correct
12 Correct 169 ms 6984 KB Output is correct
13 Correct 174 ms 7224 KB Output is correct
14 Correct 191 ms 7148 KB Output is correct
15 Correct 170 ms 7000 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 460 KB Output is correct
2 Correct 5 ms 460 KB Output is correct
3 Correct 5 ms 460 KB Output is correct
4 Correct 5 ms 460 KB Output is correct
5 Correct 7 ms 460 KB Output is correct
6 Correct 197 ms 7000 KB Output is correct
7 Correct 163 ms 6596 KB Output is correct
8 Correct 169 ms 6508 KB Output is correct
9 Correct 175 ms 6848 KB Output is correct
10 Correct 171 ms 6860 KB Output is correct
11 Correct 174 ms 7060 KB Output is correct
12 Correct 169 ms 6984 KB Output is correct
13 Correct 174 ms 7224 KB Output is correct
14 Correct 191 ms 7148 KB Output is correct
15 Correct 170 ms 7000 KB Output is correct
16 Correct 1403 ms 48096 KB Output is correct
17 Correct 1330 ms 44472 KB Output is correct
18 Correct 1460 ms 45336 KB Output is correct
19 Correct 1380 ms 46956 KB Output is correct
20 Correct 1450 ms 47172 KB Output is correct
21 Correct 1475 ms 49320 KB Output is correct
22 Correct 1440 ms 56596 KB Output is correct
23 Correct 1488 ms 57308 KB Output is correct
24 Correct 1535 ms 56612 KB Output is correct
25 Correct 1624 ms 55964 KB Output is correct