Submission #304452

#	Time	Username	Problem	Language	Result	Execution time	Memory
304452		urd05	Carnival Tickets (IOI20_tickets)	C++14	12 / 100	3077 ms	11128 KiB

tickets

#include "tickets.h"
#include <vector>
#include <bits/stdc++.h>
using namespace std;

long long dp[81][6400];
const long long INF=1e18;
int zero[80];
int one[80];
typedef pair<int,int> P;
 
long long find_maximum(int k, vector<vector<int>> v) {
	int n = v.size();
	int m = v[0].size();
	vector<vector<int>> answer(n,vector<int>(m));
	for(int i=0;i<n;i++) {
	    for(int j=0;j<m;j++) {
	        answer[i][j]=-1;
	    }
	}
	dp[0][0]=0;
	for(int i=1;i<=(n*k)/2;i++) {
	    dp[0][i]=-INF;
	}
	for(int i=1;i<=n;i++) {
	    for(int j=0;j<=(n*k)/2;j++) {
	        dp[i][j]=-INF;
	        long long sum=0;
	        for(int l=0;l<k;l++) {
	            sum-=v[i-1][l];
	        }
	        for(int l=0;l<=k&&l<=j;l++) {
	            dp[i][j]=max(dp[i][j],dp[i-1][j-l]+sum);
	            if (l!=k) {
	                sum+=v[i-1][m-l-1];
	                sum+=v[i-1][k-l-1];
	            }
	        }
	    }
	}
	long long ret=dp[n][(n*k)/2];
	int now=(n*k)/2;
	for(int i=n-1;i>=0;i--) {
	    int val;
	    long long sum=0;
	    for(int j=0;j<k;j++) {
	        sum-=v[i][j];
	    }
	    for(int j=0;j<=k&&j<=now;j++) {
	        if (dp[i][now-j]+sum==dp[i+1][now]) {
	            val=j;
	            now-=j;
	            break;
	        }
	        sum+=v[i][m-j-1];
	        sum+=v[i][k-j-1];
	    }
	    zero[i]=k-val;
	    one[i]=val;
	}
	for(int cnt=0;cnt<k;cnt++) {
	    vector<int> ind;
	    priority_queue<P> pq;
	    int pick=n/2;
	    for(int i=0;i<n;i++) {
	        if (zero[i]==0) {
	            ind.push_back(i);
	            pick--;
	            continue;
	        }
	        if (one[i]==0) {
	            continue;
	        }
	        pq.push(P(one[i]-zero[i],i));
	    }
	    for(int i=0;i<pick;i++) {
	        ind.push_back(pq.top().second);
	        pq.pop();
	    }
	    sort(ind.begin(),ind.end());
	    for(int i=0;i<n;i++) {
	        if (binary_search(ind.begin(),ind.end(),i)) {
	            answer[i][m-one[i]]=cnt;
	            one[i]--;
	        }
	        else {
	            answer[i][zero[i]-1]=cnt;
	            zero[i]--;
	        }
	    }
	}
	allocate_tickets(answer);
	return ret;
}

Compilation message (stderr)

tickets.cpp: In function 'long long int find_maximum(int, std::vector<std::vector<int> >)':
tickets.cpp:44:10: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
   44 |      int val;
      |          ^~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 16
• Subtask 3: 0 / 14
• Subtask 4: 0 / 14
• Subtask 5: 12 / 12
• Subtask 6: 0 / 23
• Subtask 7: 0 / 10