Submission #600743

#	Time	Username	Problem	Language	Result	Execution time	Memory
600743		isaachew	Uplifting Excursion (BOI22_vault)	C++17	5 / 100	5051 ms	524288 KiB

vault

#include <bits/stdc++.h>
/*
 Lift
 
 ST3-6 are split up into half-subtasks
 
 ST2.5-5.5: simple DP?
 
 5000ms time limit;
 
 20p with brute force O((n/2)^5)
 2:56 pm
 
 ST1/2: plain brute force (O(M*(sum(a_l)^2)) = O(n^5))
 
 */
std::vector<int> uplifts;
int main(){
    int m;
    long long l;
    std::cin>>m>>l;
    int maxv=0;
    for(int i=-m;i<=m;i++){
        int x;
        std::cin>>x;
        uplifts.push_back(x);
        maxv=std::max(x,maxv);
    }
    if(m*m*maxv*maxv<=100000000){
        int tmv=m*(m+1)/2*maxv+1;//really only half of the max
        std::vector<int> values1(tmv,-1000000000);//positive
        std::vector<int> values2(tmv,-1000000000);//negative
        values1[0]=0;
        values2[0]=0;
        for(int k=1;k<=m;k++){
            for(int x=0;x<uplifts[m+k];x++){
                for(int y=tmv-1-k;y>=0;y--){
                    values1[y+k]=std::max(values1[y]+1,values1[y+k]);
                }
            }
        }
        for(int k=1;k<=m;k++){
            for(int x=0;x<uplifts[m-k];x++){
                for(int y=tmv-1-k;y>=0;y--){
                    values2[y+k]=std::max(values2[y]+1,values2[y+k]);
                }
            }
        }
        int totalmax=-1;
        for(int i=0;i<tmv&&i-l<tmv;i++){
            if(i-l<0)continue;
            totalmax=std::max(totalmax,values1[i]+values2[i-l]);
        }
        if(totalmax<0){
            std::cout<<"impossible\n";
        }else{
            std::cout<<totalmax+uplifts[m]<<'\n';
        }
    }
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 15
• Subtask 3-1: 0 / 10
• Subtask 3-2: 0 / 10
• Subtask 4-1: 0 / 10
• Subtask 4-2: 0 / 10
• Subtask 5-1: 0 / 10
• Subtask 5-2: 0 / 10
• Subtask 6-1: 0 / 10
• Subtask 6-2: 0 / 10