Submission #568568

#	Time	Username	Problem	Language	Result	Execution time	Memory
568568		hoanghq2004	Shortcut (IOI16_shortcut)	C++14	71 / 100	2068 ms	71236 KiB

shortcut

#include <bits/stdc++.h>
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include "shortcut.h"

using namespace __gnu_pbds;
using namespace std;

template <typename T>
using ordered_set = tree <T, null_type, less <T>, rb_tree_tag, tree_order_statistics_node_update>;

const int N = 1e6 + 10;

long long x[N];

long long suf[N][4];
struct node {
    long long Max, Min;
    node() {
        Max = 1e18, Min = - 1e18;
    }
    node operator + (const node& other) const {
        node ret;
        ret.Max = min(Max, other.Max);
        ret.Min = max(Min, other.Min);
        return ret;
    }
};

struct SegmentTree {
    node st[N * 4];
    void add(int id, int L, int R, int i, long long Max, long long Min) {
        if (L == R) {
            st[id].Max = Max;
            st[id].Min = Min;
            return;
        }
        int mid = L + R >> 1;
        if (i <= mid) add(id * 2, L, mid, i, Max, Min);
        else add(id * 2 + 1, mid + 1, R, i, Max, Min);
        st[id] = st[id * 2] + st[id * 2 + 1];
    }
    node get(int id, int L, int R, int u, int v) {
        if (u <= L && R <= v) return st[id];
        int mid = L + R >> 1;
        if (v <= mid) return get(id * 2, L, mid, u, v);
        if (u > mid) return get(id * 2 + 1, mid + 1, R, u, v);
        return get(id * 2, L, mid, u, v) + get(id * 2 + 1, mid + 1, R, u, v);
    }
} IT;


long long find_shortcut(int n, vector<int> l, vector<int> d, int c) {
    for (int i = 0; i < n - 1; ++i) x[i + 1] = x[i] + l[i];
    vector <pair <long long, int>> ord1, ord2;
    for (int i = 0; i < n; ++i) ord1.push_back({x[i] - d[i], i});
    for (int i = 0; i < n; ++i) ord2.push_back({x[i] + d[i], i});
    sort(ord1.begin(), ord1.end());
    sort(ord2.begin(), ord2.end());
    auto check = [&](long long len) {
        long long max1 = 1e18, min1 = - 1e18;
        long long max2 = 1e18, min2 = - 1e18;
        int id = 0;
        for (auto [delta, j]: ord2) IT.add(1, 0, n - 1, j, x[j] - d[j], x[j] + d[j]);
        for (auto [delta, i]: ord1) {
            while (id < ord2.size() && get<0>(ord2[id]) <= len + delta) {
                int j = get<1>(ord2[id]);
                IT.add(1, 0, n - 1, j, 1e18, -1e18);
                ++id;
            }
            if (i + 1 == n) continue;
            node cur = IT.get(1, 0, n - 1, i + 1, n - 1);
            long long r = len - d[i] - c;
            max1 = min(max1, x[i] + cur.Max + r);
            min1 = max(min1, x[i] + cur.Min - r);
            max2 = min(max2, - x[i] + cur.Max + r);
            min2 = max(min2, - x[i] + cur.Min - r);
        }
        if (max1 < min1 || max2 < min2) return 0;
        for (int i = 0; i < n; ++i) {
            long long L = max(min1 - x[i], min2 + x[i]);
            long long R = min(max1 - x[i], max2 + x[i]);
            int j = lower_bound(x, x + n, L) - x;
            if (j == n || x[j] > R) continue;
            return 1;
        }
        return 0;
    };
    long long L = 0, R = 1e15;
    while (L < R) {
        long long mid = L + R >> 1;
        if (check(mid)) R = mid;
        else L = mid + 1;
    }
    return L;
}
//
//
//int main()
//{
//    int n, c;
//    assert(2 == scanf("%d%d", &n, &c));
//
//    std::vector<int> l(n - 1);
//    std::vector<int> d(n);
//    for (int i = 0; i < n - 1; i++)
//        assert(1 == scanf("%d", &l[i]));
//    for (int i = 0; i < n; i++)
//        assert(1 == scanf("%d", &d[i]));
//
//    long long t = find_shortcut(n, l, d, c);
//
//
//    printf("%lld\n", t);
//
//    return 0;
//}

Compilation message (stderr)

shortcut.cpp:2: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    2 | #pragma GCC optimization ("O3")
      | 
shortcut.cpp:3: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
    3 | #pragma GCC optimization ("unroll-loops")
      | 
shortcut.cpp: In member function 'void SegmentTree::add(int, int, int, int, long long int, long long int)':
shortcut.cpp:40:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   40 |         int mid = L + R >> 1;
      |                   ~~^~~
shortcut.cpp: In member function 'node SegmentTree::get(int, int, int, int, int)':
shortcut.cpp:47:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   47 |         int mid = L + R >> 1;
      |                   ~~^~~
shortcut.cpp: In lambda function:
shortcut.cpp:66:19: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   66 |         for (auto [delta, j]: ord2) IT.add(1, 0, n - 1, j, x[j] - d[j], x[j] + d[j]);
      |                   ^
shortcut.cpp:67:19: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   67 |         for (auto [delta, i]: ord1) {
      |                   ^
shortcut.cpp:68:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |             while (id < ord2.size() && get<0>(ord2[id]) <= len + delta) {
      |                    ~~~^~~~~~~~~~~~~
shortcut.cpp: In function 'long long int find_shortcut(int, std::vector<int>, std::vector<int>, int)':
shortcut.cpp:93:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   93 |         long long mid = L + R >> 1;
      |                         ~~^~~

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 7 / 7
• Subtask 5: 33 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3