Submission #1085555

#	Time	Username	Problem	Language	Result	Execution time	Memory
1085555		Sunbae	Biochips (IZhO12_biochips)	C++17	10 / 100	365 ms	524288 KiB

biochips

#include <bits/stdc++.h>
#define z exit(0)
using namespace std;
const int N = 2e5 + 5, inf = 2e8;
vector<int> g[N];
int x[N], tin[N], tout[N], timer = 1, V[N], dp[N][501], mx[501][N];
void dfs(int u){
	tin[u] = timer++;
	for(int v: g[u]) dfs(v);
	tout[u] = timer++;
}
bool cmp(int i, int j){ return tout[i] < tout[j]; }
signed main(){
	int n, m, r = 0; scanf("%d %d", &n, &m);
	for(int v = 0, u; v<n; ++v){
		scanf("%d %d", &u, x+v); --u; 
		if(u != -1) g[u].push_back(v);
		else r = v;
		V[v] = v;
		fill(dp[v], dp[v]+m+1, -inf);
	}
	dfs(r);
	sort(V, V+n, cmp);
	mx[0][0] = dp[0][0] = 0;
	mx[1][0] = dp[0][1] = x[V[0]];
	int ans = dp[0][m];
	for(int i = 1; i<n; ++i){
		int low = 0, high = i-1, idx = -1;
		while(low <= high){
			int mid = low + ((high-low)>>1);
			if(tout[V[mid]] < tin[V[i]]) low = mid+1, idx = mid;
			else high = mid-1;
		}
		for(int k = 0; k<=m; ++k){
			dp[i][k] = max(dp[i][k], dp[i-1][k]);
			if(idx != -1) dp[i][k] = max(dp[i][k], mx[k-1][idx] + x[V[i]]);
			mx[k][i] = dp[i][k];
		}	
		ans = max(ans, dp[i][m]);
		for(int k = 0; k<=m; ++k) mx[k][i] = max(mx[k][i], mx[k][i-1]);
	}
	assert(ans == mx[m][n-1]); 
	printf("%d", mx[m][n-1]);
}

Compilation message (stderr)

biochips.cpp: In function 'int main()':
biochips.cpp:14:24: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   14 |  int n, m, r = 0; scanf("%d %d", &n, &m);
      |                   ~~~~~^~~~~~~~~~~~~~~~~
biochips.cpp:16:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |   scanf("%d %d", &u, x+v); --u;
      |   ~~~~~^~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 100