oj.uz

Submission #771786

# Submission time Handle Problem Language Result Execution time Memory
771786 2023-07-03T09:18:05 Z drdilyor Radio Towers (IOI22_towers) C++17
17 / 100
 1739 ms 32284 KB 
#include <bits/stdc++.h>
#include "towers.h"
using namespace std;
using ll = long long;
constexpr int inf = 1e9;

template<typename T, typename Op>
struct SparseTable {
    vector<vector<T>> sparse;
    Op accum_func;

    SparseTable() = default;

    SparseTable(const vector<T>& arr, const Op func) : accum_func(func) {
        int n = arr.size();
        int logn = 32 - __builtin_clz(n);
        sparse.resize(logn, vector<T>(n));
        sparse[0] = arr;
        for (int lg = 1; lg < logn; lg++) {
            for (int i = 0; i + (1 << lg) <= n; i++) {
                sparse[lg][i] = accum_func(sparse[lg - 1][i], sparse[lg - 1][i + (1 << (lg - 1))]);
            }
        }
    }

    T find(int l, int r) { // [l, r]
        r++;
        int cur_log = 31 - __builtin_clz(r - l);
        return accum_func(sparse[cur_log][l], sparse[cur_log][r - (1 << cur_log)]);
    }
};

struct SegmentTree {
    using T = vector<int>;
    using S = int;
    const T id = {};
    inline T single(S v) { return {v}; }

    T merge(const T& l, const T& r) {
        T res(l.size() + r.size());
        std::merge(l.cbegin(), l.cend(),
              r.cbegin(), r.cend(),
              res.begin());
        return res;
    }

    int n;
    vector<T> tree;

    SegmentTree() = default;
    void init(vector<S> arr) {
        n = arr.size();
        tree.resize(n * 2, id);
        for (int i = 0; i < n; i++) {
            tree[i + n] = single(arr[i]);
        }
        build();
    }

    void build() {
        for (int i = n-1; i >= 1; i--) {
            tree[i] = merge(tree[i*2], tree[i*2 + 1]);
        }
    }

    void update(int i, S v) {
        tree[i+=n] = single(v);
        for (i /= 2; i >= 1; i/= 2)
            tree[i] = merge(tree[i*2], tree[i*2+1]);
    }

    tuple<int,int,int> query(int l, int r, int x) {
        int cnt = 0;
        int left = -1, right = -1;
        l += n; r += n;
        while (l <= r) {
            if (l % 2 == 1) {
                if (left ==-1) left = leftmost(l, x);
                cnt += count_ge(tree[l++], x);
            }
            if (r % 2 == 0) {
                if (right == -1) right = rightmost(r, x);
                cnt += count_ge(tree[r--], x);
            }
            l /= 2; r /= 2;
        }
        return {cnt, left, right};
    }

    int count_ge(T& v, int x) {
        return v.end() - lower_bound(v.begin(), v.end(), x);
    }

    int leftmost(int v, int x, bool rev=0) {
        if (tree[v].back() < x) return -1;
        while (v < n) {
            if (tree[v*2+rev].back() >= x) v = v * 2 +rev;
            else v = v * 2 + 1 -rev;
        }
        return v - n;
    }
    int rightmost(int v, int x) {
        return leftmost(v, x, 1);
    }
};


int st_min(int a, int b) { return min(a, b); }
int st_max(int a, int b) { return max(a, b); }

int n;
vector<int> h, ix;
SparseTable<int, decltype(&st_min)> hmax;
SparseTable<int, decltype(&st_max)> hmin;

vector<int> start;
SegmentTree ans;

int find_left(int i, int d) {
    int l = -1, r = i;
    while (l < r-1) {
        int mid = (l+r) / 2;
        if (hmax.find(mid, i) - h[i] >= d)
            l = mid;
        else r = mid;
    }
    return l;
}

int find_right(int i, int d) {
    int l = i, r = n;
    while (l < r-1) {
        int mid = (l+r) / 2;
        if (hmax.find(i, mid) - h[i] >= d)
            r = mid;
        else l = mid;
    }
    return r;
}

void init(int N, std::vector<int> H) {
    n = N, h = H;
    ix.resize(n);
    start.resize(n);
    iota(ix.begin(), ix.end(), 0);
    sort(ix.begin(), ix.end(), [&](int i, int j) {
            return h[i] < h[j];
            });
    hmax = SparseTable(h, st_max);
    hmin = SparseTable(h, st_min);
    const int L = 0, R = n-1;

    for (int i = 0; i < n;i++) {
        int lD = 0, rD = inf+1;
        while (lD < rD-1) {
            int D = (lD + rD) / 2;
            bool ok = 1;

            int lg = find_left(i, D);
            if (hmin.find(lg+1, i) < h[i]) ok = 0;

            int rg = find_right(i, D);
            if (hmin.find(i, rg-1) < h[i]) ok = 0;

            if (ok) lD = D;
            else rD = D;
        }
        start[i] = lD;
    }
    ans.init(start);
}

int max_towers(int L, int R, int D) {
    auto [cnt, left, right] = ans.query(L, R, D);
    int lg = find_left(left, D);
    int rg = find_right(right, D);
    if (lg > L && hmin.find(L, lg) <= h[lg]-D) cnt++;
    if (rg < R && hmin.find(rg, R) <= h[rg]-D) cnt++;
    return cnt;
}

Compilation message

towers.cpp: In function 'void init(int, std::vector<int>)':
towers.cpp:151:15: warning: unused variable 'L' [-Wunused-variable]
  151 |     const int L = 0, R = n-1;
      |               ^
towers.cpp:151:22: warning: unused variable 'R' [-Wunused-variable]
  151 |     const int L = 0, R = n-1;
      |                      ^

Subtask #1
0 / 4.0

# Verdict Execution time Memory Grader output
1 Incorrect 838 ms 18652 KB 1st lines differ - on the 1st token, expected: '1', found: '0'
2 Halted 0 ms 0 KB -

Subtask #2
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 336 KB Output is correct
2 Correct 12 ms 720 KB Output is correct
3 Correct 10 ms 720 KB Output is correct
4 Correct 10 ms 720 KB Output is correct
5 Correct 10 ms 772 KB Output is correct
6 Correct 10 ms 768 KB Output is correct
7 Incorrect 10 ms 680 KB 1st lines differ - on the 1st token, expected: '34', found: '33'
8 Halted 0 ms 0 KB -

Subtask #3
0 / 12.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 336 KB Output is correct
2 Correct 12 ms 720 KB Output is correct
3 Correct 10 ms 720 KB Output is correct
4 Correct 10 ms 720 KB Output is correct
5 Correct 10 ms 772 KB Output is correct
6 Correct 10 ms 768 KB Output is correct
7 Incorrect 10 ms 680 KB 1st lines differ - on the 1st token, expected: '34', found: '33'
8 Halted 0 ms 0 KB -

Subtask #4
0 / 14.0

# Verdict Execution time Memory Grader output
1 Incorrect 1532 ms 31960 KB 29th lines differ - on the 1st token, expected: '9839', found: '9838'
2 Halted 0 ms 0 KB -

Subtask #5
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 370 ms 7356 KB Output is correct
2 Correct 1511 ms 32228 KB Output is correct
3 Correct 1594 ms 32228 KB Output is correct
4 Correct 1515 ms 32224 KB Output is correct
5 Correct 1586 ms 32236 KB Output is correct
6 Correct 1739 ms 32228 KB Output is correct
7 Correct 1549 ms 32228 KB Output is correct
8 Correct 1547 ms 32228 KB Output is correct
9 Correct 1460 ms 32224 KB Output is correct
10 Correct 1555 ms 32228 KB Output is correct
11 Correct 1544 ms 32232 KB Output is correct
12 Correct 830 ms 32224 KB Output is correct
13 Correct 836 ms 32232 KB Output is correct
14 Correct 817 ms 32232 KB Output is correct
15 Correct 784 ms 32268 KB Output is correct
16 Correct 793 ms 32232 KB Output is correct
17 Correct 782 ms 31216 KB Output is correct
18 Correct 810 ms 32232 KB Output is correct
19 Correct 796 ms 32228 KB Output is correct
20 Correct 821 ms 32232 KB Output is correct
21 Correct 814 ms 32224 KB Output is correct
22 Correct 838 ms 32284 KB Output is correct
23 Correct 816 ms 32236 KB Output is correct
24 Correct 767 ms 32228 KB Output is correct
25 Correct 767 ms 32224 KB Output is correct
26 Correct 778 ms 32224 KB Output is correct
27 Correct 788 ms 32228 KB Output is correct
28 Correct 10 ms 720 KB Output is correct
29 Correct 10 ms 720 KB Output is correct
30 Correct 10 ms 772 KB Output is correct
31 Correct 10 ms 720 KB Output is correct
32 Correct 10 ms 720 KB Output is correct
33 Correct 5 ms 384 KB Output is correct
34 Correct 10 ms 764 KB Output is correct
35 Correct 10 ms 720 KB Output is correct
36 Correct 10 ms 720 KB Output is correct
37 Correct 10 ms 768 KB Output is correct
38 Correct 10 ms 768 KB Output is correct
39 Correct 10 ms 772 KB Output is correct
40 Correct 9 ms 720 KB Output is correct
41 Correct 10 ms 720 KB Output is correct
42 Correct 10 ms 720 KB Output is correct
43 Correct 10 ms 772 KB Output is correct

Subtask #6
0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 336 KB Output is correct
2 Correct 12 ms 720 KB Output is correct
3 Correct 10 ms 720 KB Output is correct
4 Correct 10 ms 720 KB Output is correct
5 Correct 10 ms 772 KB Output is correct
6 Correct 10 ms 768 KB Output is correct
7 Incorrect 10 ms 680 KB 1st lines differ - on the 1st token, expected: '34', found: '33'
8 Halted 0 ms 0 KB -

Subtask #7
0 / 23.0

# Verdict Execution time Memory Grader output
1 Incorrect 838 ms 18652 KB 1st lines differ - on the 1st token, expected: '1', found: '0'
2 Halted 0 ms 0 KB -