Submission #757890

#	Time	Username	Problem	Language	Result	Execution time	Memory
757890		jasmin	Collecting Stamps 3 (JOI20_ho_t3)	C++17	100 / 100	104 ms	145332 KiB

ho_t3

#include<bits/stdc++.h>
using namespace std;
#define int long long

const int N=210;
int dp[N][N][N][2];

const int INF=1e18;

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    int n, tot;
    cin >> n >> tot;

    vector<int> x(n+2);
    x[0]=0; x[n+1]=tot;
    for(int i=1; i<=n; i++){
        cin >> x[i];
    }

    vector<int> t(n+2);
    t[0]=-1; t[n+1]=-1;
    for(int i=1; i<=n; i++){
        cin >> t[i];
    }


    //initialize
    for(int i=0; i<N; i++){
        for(int j=0; j<N; j++){
            for(int k=0; k<N; k++){
                for(int x=0; x<2; x++){
                    dp[i][j][k][x]=INF;
                }
            }
        }
    }
    dp[0][0][0][0]=0;
    dp[0][0][0][1]=0;

    for(int l=0; l<n; l++){
        for(int r=0; r<n; r++){
            if(l+r>=n) continue;

            for(int c=0; c<n; c++){

                for(int loc=0; loc<2; loc++){
                    if(dp[l][r][c][loc]==INF) continue;

                    int cor;
                    if(loc==0){
                        cor = x[n+1-l];
                    }
                    else{
                        cor = x[r];
                    }

                    //walk right
                    int distright = 0;
                    if(loc==0){
                        distright = (tot-cor) + x[r+1];
                    }
                    else{
                        distright = x[r+1] - cor;
                    }

                    dp[l][r+1][c][1] = min(dp[l][r+1][c][1], dp[l][r][c][loc] + distright);
                    //dp[l][r+1][c][0] = min(dp[l][r+1][c][0], dp[l][r][c][loc] + 2*distright);
                    if( dp[l][r][c][loc] + distright <= t[r+1] ){

                        dp[l][r+1][c+1][1] = min( dp[l][r+1][c+1][1], dp[l][r][c][loc] + distright );
                        //dp[l][r+1][c+1][0] = min( dp[l][r+1][c+1][0], dp[l][r][c][loc] + 2*distright);
                    }


                    //walk left
                    int distleft=0;
                    if(loc==0){
                        distleft = cor - x[n+1 - (l+1)];
                    }
                    else{
                        distleft = tot - x[n+1 - (l+1)] + cor;
                    }

                    dp[l+1][r][c][0] = min(dp[l+1][r][c][0], dp[l][r][c][loc] + distleft);
                    //dp[l+1][r][c][1] = min(dp[l+1][r][c][1], dp[l][r][c][loc] + 2*distleft);
                    if( dp[l][r][c][loc] + distleft <= t[n+1-(l+1)]){

                        dp[l+1][r][c+1][0] = min(dp[l+1][r][c+1][0], dp[l][r][c][loc] + distleft);
                        //dp[l+1][r][c+1][1] = min(dp[l+1][r][c+1][1], dp[l][r][c][loc] + 2*distleft);
                    }

                }

            }
        }
    }

    //finding the largest one
    int ans=0;
    for(int i=0; i<=n; i++){
        for(int j=0; j<=n; j++){
            for(int k=0; k<=n; k++){
                //cout << i << " " << j << " " << k <<  ": " << dp[i][j][k][0] << ", " << dp[i][j][k][1] << "\n";

                for(int x=0; x<2; x++){


                    if(dp[i][j][k][x] != INF){
                        ans = max(ans, k);
                    }

                }
            }
        }
    }
    cout << ans << "\n";
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 10 / 10
• Subtask 4: 75 / 75