# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1128667 | FanOfWilliamLin | Toll (BOI17_toll) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
using namespace std;
int k, n, m, o;
int dp[50000][17][5][5], ans[5][5], tmp[5][5];
void combine(int& target[5][5], int a[5][5], int b[5][5]) {
for (int x = 0; x < k; x++) {
for (int y = 0; y < k; y++) {
for (int z = 0; z < k; z++) {
target[x][y] = min(target[x][y], a[x][z] + b[z][y]);
}
}
}
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
cin >> k >> n >> m >> o;
memset(dp, 0x3f, sizeof dp);
while (m--) {
int a, b, t;
cin >> a >> b >> t;
dp[a / k][0][a % k][b % k] = t;
}
for (int j = 1; j < 17; j++) {
for (int i = 0; i + (1 << j) < (n + k - 1) / k; i++) {
combine(dp[i][j], dp[i][j - 1], dp[i + (1 << j - 1)][j - 1]);
}
}
while (o--) {
int a, b;
cin >> a >> b;
memset(ans, 0x3f, sizeof ans);
for (int i = 0; i < 5; i++) ans[i][i] = 0;
for (int curr = a / k, dest = b / k, i = 16; ~i; i--) {
if (curr + (1 << i) <= dest) {
memset(tmp, 0x3f, sizeof tmp);
combine(tmp, ans, dp[curr][i]);
memcpy(ans, tmp, sizeof ans);
curr += (1 << i);
}
}
cout << (ans[a % k][b % k] == 0x3f3f3f3f ? -1 : ans[a % k][b % k]) << '\n';
}
return 0;
}