Submission #1093554

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093554		Thanhs	Toll (BOI17_toll)	C++14	0 / 100	591 ms	169520 KiB

toll

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

#define fi first
#define se second
#define int long long
#define endl '\n'
#define setmin(x, y) x = ((x) < (y) ? (x) : (y))
#define setmax(x, y) x = ((x) > (y) ? (x) : (y))

mt19937 hdp(chrono::high_resolution_clock::now().time_since_epoch().count());
int rand(int l, int r){return l + ((hdp() % (r - l + 1)) + r - l + 1) % (r - l + 1);}

const int NM = 5e4 + 5;
const int LG = 16;
const int inf = 1e9;

int n, m, q, k;
map<int, int> dp[NM];

struct node
{
    int dt[5][5];
    node() {for (int i = 0; i < k; i++) for (int j = 0; j < k; j++) dt[i][j] = inf;}
    node operator*(const node& o)
    {
        node res;
        for (int i = 0; i < k; i++)
            for (int j = 0; j < k; j++)
                for (int t = 0; t < k; t++)
                    setmin(res.dt[i][j], dt[i][t] + o.dt[t][j]);
        return res;
    }
}st[NM][LG];

void solve()    
{
    cin >> k >> n >> m >> q;
    for (int i = 0; i < n; i++)
    {
        for (int j = (i / k - 1) * k; j < (i / k + 2) * k; j++)
            if (j >= 0 && j < n)
                dp[i][j] = inf;
        dp[i][i] = 0;
    }
    for (int i = 1; i <= m; i++)
    {
        int u, v, w;
        cin >> u >> v >> w;
        setmin(dp[u][v], w);
        setmin(dp[v][u], w);
    }
    for (int _ = 0; _ <= __lg(n); _++)
        for (int i = 0; i < n; i++)
            for (int j = (i / k - 1) * k; j < (i / k + 2) * k; j++)
                if (j >= 0 && j < n)
                {
                    for (int o = (i / k - 1) * k; o < (i / k + 2) * k; o++)
                    {
                        if (o < 0 || o >= n || dp[o].find(j) == dp[o].end())
                            continue;
                        setmin(dp[i][j], dp[i][o] + dp[o][j]);
                    }
                }
    for (int i = 0; i < n - 1; i++)
        for (int j = 0; j < k; j++)
            st[i / k][0].dt[i % k][j] = dp[i][(i / k + 1) * k + j];
    for (int lg = 1; lg < __lg(n); lg++)
        for (int i = 0; i + (1 << lg) - 1 <= n / k; i++)
            st[i][lg] = st[i][lg - 1] * st[i + (1 << lg - 1)][lg - 1];
    while (q--)
    {
        int u, v;
        cin >> u >> v;
        if (u > v)
            swap(u, v);
        if (u / k == v / k)
            cout << (dp[u][v] == inf ? -1 : dp[u][v]) << endl;
        else
        {
            node res;
            for (int i = 0; i < k; i++)
                res.dt[0][i] = dp[u][(u / k + 1) * k + i];
            int t = v / k - u / k - 1, cur = u / k + 1;
            for (int i = t ? __lg(t) : -1; i >= 0; i--)
                if (t & (1 << i))
                {
                    res = res * st[cur][i];
                    cur += 1 << i;
                }
            cout << (res.dt[0][v % k] == inf ? -1 : res.dt[0][v % k]) << endl;
        }
    }
}

signed main()
{
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);
    if (fopen("in.txt", "r")) 
    {
        freopen("in.txt", "r", stdin);
        freopen("out.txt", "w", stdout);
    }
    // freopen("storagebox.inp", "r", stdin);
    // freopen("storagebox.out", "w", stdout);
    int tc = 1; 
    // cin >> tc;
    while (tc--)
        solve();
}

Compilation message (stderr)

toll.cpp: In function 'void solve()':
toll.cpp:70:57: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   70 |             st[i][lg] = st[i][lg - 1] * st[i + (1 << lg - 1)][lg - 1];
      |                                                      ~~~^~~
toll.cpp: In function 'int main()':
toll.cpp:101:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |         freopen("in.txt", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
toll.cpp:102:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  102 |         freopen("out.txt", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 7
• Subtask 2: 0 / 10
• Subtask 3: 0 / 8
• Subtask 4: 0 / 31
• Subtask 5: 0 / 44