Submission #1110740

#	Time	Username	Problem	Language	Result	Execution time	Memory
1110740		nhphuc	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	330 ms	262144 KiB

skyscraper

#include <bits/stdc++.h>
using namespace std;

#define iii tuple<int, int, int>

const int N = 30500;
const int block = 200;

int n, m, b[N], v[N], dp[N][block + 7], ans = -1;
vector<int> pw[N];
vector<pair<int, int>> Q[N * block];

int32_t main (){
    ios::sync_with_stdio(false); cin.tie(nullptr);
    if (fopen("test.inp", "r")){
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    cin >> n >> m;
    for (int i = 0; i < n; ++i)
        for (int j = 0; j <= block + 1; ++j)
            dp[i][j] = -1;
    for (int i = 1; i <= m; ++i){
        cin >> b[i] >> v[i];
        pw[b[i]].push_back(v[i]);
        if (i == 1)
            Q[0].push_back({b[i], v[i]});
    }
    for (int D = 0; D < N * block; ++D){
        for (pair<int, int> it : Q[D]){
            int u = it.first;
            int t = it.second; t = min(t, block + 1);
            if (dp[u][t] != -1)
                continue;
            dp[u][t] = D;
            if (u == b[2])
                ans = min((ans == -1 ? (int)1e16 : ans), D);
            if (t <= block){
                if (u - t >= 0 && dp[u - t][t] == -1)
                    Q[D + 1].push_back({u - t, t});
                if (u + t < n && dp[u + t][t] == -1)
                    Q[D + 1].push_back({u + t, t});
            }
            for (int X : pw[u]){
                if (X <= block){
                    if (u - X >= 0 && dp[u - X][X] == -1)
                        Q[D + 1].push_back({u - X, X});
                    if (u + X < n && dp[u + X][X] == -1)
                        Q[D + 1].push_back({u + X, X});
                } else {
                    for (int i = u - X; i >= 0; i -= X)
                        if (dp[i][block + 1] == -1)
                            Q[D + (u - i) / X].push_back({i, X});
                    for (int i = u + X; i < n; i += X)
                        if (dp[i][block + 1] == -1)
                            Q[D + (i - u) / X].push_back({i, X});
                }
            }
        }
    }
    cout << ans << "\n";
}

Compilation message (stderr)

skyscraper.cpp: In function 'int32_t main()':
skyscraper.cpp:16:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:17:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 14 / 14
• Subtask 4: 21 / 21
• Subtask 5: 0 / 43