Submission #979322

#	Time	Username	Problem	Language	Result	Execution time	Memory
979322		chautanphat	Toll (BOI17_toll)	C++14	100 / 100	74 ms	83832 KiB

toll

#include <bits/stdc++.h>
 
using namespace std;
 
const int N = 5e4;
int k, n, m, o, cost[N][5][5], ans[__lg(N)+1][N][5][5], mask[N];
 
void dnc(int l, int r, int level = 0)
{
    if (l == r) return;
    int mid = (l+r)/2;
    
    for (int a = 0; a < k; a++)
        ans[level][mid][a][a] = 0;
    for (int i = mid-1; i >= l; i--)
        for (int a = 0; a < k; a++)
            for (int b = 0; b < k; b++)
                for (int c = 0; c < k; c++)
                    ans[level][i][a][c] = min(ans[level][i][a][c], ans[level][i+1][b][c]+cost[i][a][b]);
    for (int a = 0; a < k; a++)
        for (int b = 0; b < k; b++)
            ans[level][mid+1][a][b] = cost[mid][a][b];
    for (int i = mid+2; i <= r; i++)
        for (int a = 0; a < k; a++)
            for (int b = 0; b < k; b++)
                for (int c = 0; c < k; c++)
                    ans[level][i][c][a] = min(ans[level][i][c][a], ans[level][i-1][c][b]+cost[i-1][b][a]);
 
    for (int i = mid+1; i <= r; i++) mask[i] |= 1<<level;
 
    dnc(l, mid, level+1);
    dnc(mid+1, r, level+1);
}
 
int main()
{    
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    
    cin >> k >> n >> m >> o;
 
    for (int i = 0; i < n; i++)
        for (int a = 0; a < k; a++)
            for (int b = 0; b < k; b++)
                cost[i][a][b] = 1e9;
    for (int level = 0; (1<<level) < n; level++)
        for (int i = 0; i < n; i++)
            for (int a = 0; a < k; a++)
                for (int b = 0; b < k; b++)
                    ans[level][i][a][b] = 1e9;
 
    for (int i = 0; i < m; i++)
    {
        int a, b, t;
        cin >> a >> b >> t;
        cost[a/k][a%k][b%k] = t;
    }
 
    dnc(0, (n-1)/k);
 
    for (int i = 0; i < o; i++)
    {
        int a, b;
        cin >> a >> b;
        if (a/k == b/k)
        {
            cout << -1 << '\n';
            continue;
        }
        int level = __builtin_ctz(mask[a/k]^mask[b/k]), res = 1e9;
        for (int j = 0; j < k; j++)
            res = min(res, ans[level][a/k][a%k][j]+ans[level][b/k][j][b%k]);
        cout << (res == 1e9 ? -1 : res) << '\n';
    }
    return 0;
}

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