Submission #90728

#	Time	Username	Problem	Language	Result	Execution time	Memory
90728		mirbek01	Biochips (IZhO12_biochips)	C++17	100 / 100	751 ms	21028 KiB

biochips

# include <bits/stdc++.h>

using namespace std;

const int N = 3e5 + 2;

int n, m, rt, a[N], tin[N], tout[N], timer;
long long dp[2][N], x[N];
vector <int> g[N];

void dfs(int v){
      tin[v] = ++  timer;
      for(int to : g[v]){
            dfs(to);
      }
      tout[v] = timer;
}

int main(){
      scanf("%d %d", &n, &m);

      for(int i = 1; i <= n; i ++){
            int p;
            scanf("%d %lld", &p, x + i);
            if(!p)
                  rt = i;
            else {
                  g[p].push_back(i);
            }
      }

      dfs(rt);

      fill(dp[1], dp[1] + n + 2, -1e18);

      for(int i = 1; i <= n; i ++){
            dp[1][tout[i]] = max(x[i], dp[1][tout[i]]);
      }

      for(int i = 2; i <= m; i ++){
            int cur = i % 2;
            int pre = cur ^ 1;
            fill(dp[cur], dp[cur] + n + 2, -1e18);
            for(int j = 1; j <= n; j ++)
                  dp[pre][j] = max(dp[pre][j], dp[pre][j - 1]);
            for(int j = 1; j <= n; j ++){
                  dp[cur][tout[j]] = max(dp[cur][tout[j]], dp[pre][tin[j] - 1] + x[j]);
            }
      }

      long long ans = 0;

      for(int i = 1; i <= n; i ++)
            ans = max(ans, dp[m % 2][i]);

      cout << ans << endl;
}

Compilation message (stderr)

biochips.cpp: In function 'int main()':
biochips.cpp:20:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d %d", &n, &m);
       ~~~~~^~~~~~~~~~~~~~~~~
biochips.cpp:24:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%d %lld", &p, x + i);
             ~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100