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mirror of https://git.sb/baoshuo/OI-codes.git synced 2024-11-23 20:28:48 +00:00

P3354 [IOI2005]Riv 河流

https://www.luogu.com.cn/record/102483854
This commit is contained in:
Baoshuo Ren 2023-02-19 10:20:14 +08:00
parent 141a85eb62
commit 3266ee94cc
Signed by: baoshuo
GPG Key ID: 00CB9680AB29F51A

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Luogu/P3354/P3354.cpp Normal file
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#include <iostream>
#include <vector>
using std::cin;
using std::cout;
const char endl = '\n';
const int N = 105;
int n, k, w[N], v[N], d[N], dis[N];
int f[N][2][N][N];
std::vector<int> g[N], st;
void dfs(int u) {
st.emplace_back(u);
for (int v : g[u]) {
dis[v] = dis[u] + d[v];
dfs(v);
for (int t : st) {
for (int i = k; i >= 0; i--) {
f[u][0][t][i] += f[v][0][t][0];
f[u][1][t][i] += f[v][0][u][0];
for (int j = 1; j <= i; j++) {
f[u][0][t][i] = std::min(f[u][0][t][i], f[v][0][t][j] + f[u][0][t][i - j]);
f[u][1][t][i] = std::min(f[u][1][t][i], f[v][0][u][j] + f[u][1][t][i - j]);
}
}
}
}
for (int t : st) {
for (int i = k; i; i--) {
f[u][0][t][i] = std::min(f[u][0][t][i] + w[u] * (dis[u] - dis[t]), f[u][1][t][i - 1]);
}
f[u][0][t][0] += w[u] * (dis[u] - dis[t]);
}
st.pop_back();
}
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> k;
for (int i = 1; i <= n; i++) {
cin >> w[i] >> v[i] >> d[i];
g[v[i]].emplace_back(i);
}
dfs(0);
cout << f[0][0][0][k] << endl;
return 0;
}