oj.uz

Submission #414217

# Submission time Handle Problem Language Result Execution time Memory
414217 2021-05-30T09:18:57 Z shivensinha4 Election (BOI18_election) C++17
100 / 100
 768 ms 49768 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;

//    cout << ans + tree.mx(0, n-1) - tree.tree[0].sum << endl;
}

Subtask #1
28.0 / 28.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 460 KB Output is correct
2 Correct 2 ms 460 KB Output is correct
3 Correct 2 ms 460 KB Output is correct
4 Correct 3 ms 460 KB Output is correct
5 Correct 2 ms 496 KB Output is correct

Subtask #2
54.0 / 54.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 460 KB Output is correct
2 Correct 2 ms 460 KB Output is correct
3 Correct 2 ms 460 KB Output is correct
4 Correct 3 ms 460 KB Output is correct
5 Correct 2 ms 496 KB Output is correct
6 Correct 77 ms 6948 KB Output is correct
7 Correct 73 ms 6524 KB Output is correct
8 Correct 65 ms 6504 KB Output is correct
9 Correct 70 ms 6844 KB Output is correct
10 Correct 91 ms 6872 KB Output is correct
11 Correct 73 ms 7032 KB Output is correct
12 Correct 91 ms 7076 KB Output is correct
13 Correct 71 ms 7108 KB Output is correct
14 Correct 83 ms 6980 KB Output is correct
15 Correct 83 ms 6884 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 460 KB Output is correct
2 Correct 2 ms 460 KB Output is correct
3 Correct 2 ms 460 KB Output is correct
4 Correct 3 ms 460 KB Output is correct
5 Correct 2 ms 496 KB Output is correct
6 Correct 77 ms 6948 KB Output is correct
7 Correct 73 ms 6524 KB Output is correct
8 Correct 65 ms 6504 KB Output is correct
9 Correct 70 ms 6844 KB Output is correct
10 Correct 91 ms 6872 KB Output is correct
11 Correct 73 ms 7032 KB Output is correct
12 Correct 91 ms 7076 KB Output is correct
13 Correct 71 ms 7108 KB Output is correct
14 Correct 83 ms 6980 KB Output is correct
15 Correct 83 ms 6884 KB Output is correct
16 Correct 732 ms 48064 KB Output is correct
17 Correct 558 ms 44452 KB Output is correct
18 Correct 609 ms 45284 KB Output is correct
19 Correct 691 ms 47012 KB Output is correct
20 Correct 701 ms 47272 KB Output is correct
21 Correct 700 ms 49364 KB Output is correct
22 Correct 768 ms 48964 KB Output is correct
23 Correct 709 ms 49768 KB Output is correct
24 Correct 674 ms 48964 KB Output is correct
25 Correct 719 ms 48240 KB Output is correct