Submission #519313

#	Time	Username	Problem	Language	Result	Execution time	Memory
519313		Monarchuwu	Biochips (IZhO12_biochips)	C++17	100 / 100	268 ms	401700 KiB

biochips

#include<iostream>
#include<algorithm>
#include<cstring>
#include<numeric>
#include<vector>
using namespace std;
typedef long long ll;

const int N = 2e5 + 8;
int n, m, a[N];
vector<int> g[N];

int tme, tin[N], tout[N];
int inv[N];
void dfs(int u) {
    inv[tin[u] = ++tme] = u;
    for (int v : g[u]) dfs(v);
    tout[u] = tme;
}

int dp[N][502];
int main() {
 	cin.tie(NULL)->sync_with_stdio(false);
    cin >> n >> m;
    for (int i = 1, p; i <= n; ++i) {
        cin >> p >> a[i];
        g[p].push_back(i);
    }
    dfs(g[0][0]);

    memset(dp[n + 1], 0x80, sizeof(dp[n + 1]));
    dp[n + 1][0] = 0;
    for (int i = n; i; --i) {
        copy(dp[i + 1], dp[i + 1] + m + 1, dp[i]);
        for (int j = 1; j <= m; ++j)
            dp[i][j] = max(dp[i][j], dp[tout[inv[i]] + 1][j - 1] + a[inv[i]]);
    }
    cout << (dp[1][m] < 0 ? -1 : dp[1][m]) << '\n';
}
/**  /\_/\
 *  (= ._.)
 *  / >0  \>1
**/

• Subtask 1: 100 / 100