#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef pair<int, int> pi;
#define debug(x) cerr << #x << ": " << x << endl
#define debug2(x, y) debug(x), debug(y)
#define repn(i, a, b) for(int i = (int)(a); i < (int)(b); i++)
#define rep(i, a) for(int i = 0; i < (int)(a); i++)
#define all(v) v.begin(), v.end()
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define se second
#define sq(x) ((x) * (x))
const int mxN = 2e5 + 5;
template<class T> T gcd(T a, T b){ return ((b == 0) ? a : gcd(b, a % b)); }
int n, m;
int rt, pos = 0;
int a[mxN], inv[mxN], st[mxN], nxt[mxN];
int dp[mxN][505];
vi g[mxN];
void chmax(int &a, int b){
a = max(a, b);
}
void dfs(int cur){
st[cur] = pos++;
inv[pos - 1] = cur;
for(int u : g[cur]) dfs(u);
nxt[st[cur]] = pos;
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
//freopen("input.in", "r", stdin);
//freopen("output.out", "w", stdout);
cin >> n >> m;
rep(i, n){
int p;
cin >> p >> a[i];
p--;
if(~p) g[p].pb(i);
else rt = i;
}
dfs(rt);
memset(dp, -1, sizeof(dp));
rep(i, mxN) dp[i][0] = 0;
rep(k, n){
int i = inv[k];
rep(j, m + 1){
//we are updating from dp[i][j]
if(~dp[k][j]) chmax(dp[k + 1][j], dp[k][j]);
if(j < m && ~dp[k][j]) chmax(dp[nxt[k]][j + 1], dp[k][j] + a[i]);
}
}
int ans = 0;
rep(i, n + 1) ans = max(ans, dp[i][m]);
cout << ans << endl;
return 0;
}
/*
Things to look out for:
- Integer overflows
- Make sure that max is large enough (2e9, 4e18)
- Special cases
Be careful!
*/
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
190 ms |
400480 KB |
Output is correct |
| 2 |
Correct |
188 ms |
400356 KB |
Output is correct |
| 3 |
Correct |
194 ms |
400484 KB |
Output is correct |
| 4 |
Correct |
196 ms |
400740 KB |
Output is correct |
| 5 |
Correct |
197 ms |
400744 KB |
Output is correct |
| 6 |
Correct |
201 ms |
400740 KB |
Output is correct |
| 7 |
Correct |
505 ms |
405452 KB |
Output is correct |
| 8 |
Correct |
509 ms |
405536 KB |
Output is correct |
| 9 |
Correct |
643 ms |
405604 KB |
Output is correct |
| 10 |
Correct |
812 ms |
406172 KB |
Output is correct |
