Submission #1278180

#	Time	Username	Problem	Language	Result	Execution time	Memory
1278180		trinm01	Collecting Stamps 3 (JOI20_ho_t3)	C++20	100 / 100	99 ms	132196 KiB

ho_t3

// #pragma GCC optimize("O3")
// #pragma GCC optimization("Ofast,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;

#define int long long 
#define ll long long
#define FOR(i, l, r) for (int i = (l); i <= (r); i++)
#define FOD(i, r, l) for (int i = (r); i >= (l); i--)
#define fi first
#define se second
#define pii pair<int, int>

const ll mod = 1e9 + 7;
const int MAXN = 2e2 + 5;
const ll oo = 1e18 + 7;  
const int base = 10;

int n, L;
int x[MAXN], t[MAXN];

int ps1[MAXN], ps2[MAXN];

int f[MAXN][MAXN][2][MAXN];


signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    
    // freopen("test.txt", "r", stdin);
    // freopen("o2.out", "w", stdout);

    if(fopen(".inp", "r")){
        freopen(".inp", "r", stdin);
        freopen(".out", "w", stdout);
    }

    cin >> n >> L;
    FOR(i, 1, n){
    	cin >> x[i];
    }
    FOR(i, 1, n){
    	cin >> t[i];
    }
    x[n+1]=L;
    FOR(i, 1, n){
    	ps1[i]=x[i];
    }
    FOD(i, n, 1){
    	ps2[i]=(L-x[i]);
	}
    
    FOR(i, 0, n+1){
    	FOR(j, 0, n+1){
    		FOR(ty, 0, 1){
    			FOR(sum, 0, n){
    				f[i][j][ty][sum]=oo;
    			}
    		}
    	}
    }
    f[0][n+1][0][0]=0;
    f[0][n+1][1][0]=0;
    int res=0;
    FOR(i, 0, n){
    	FOD(j, n+1, i+1){
    		FOR(ty, 0, 1){
    			FOR(sum, 0, n){
    				if(i==0 && j==n+1) continue;
    				int ans=oo;
    				if(ty==0 && i-1>=0){
    					if(sum!=0 && f[i-1][j][0][sum-1]+x[i]-x[i-1]<=t[i]){
							ans=min(ans, f[i-1][j][0][sum-1]+x[i]-x[i-1]);	
						}
						ans=min(ans, f[i-1][j][0][sum]+x[i]-x[i-1]);
						
						if(sum!=0 && f[i-1][j][1][sum-1]+ps2[j]+ps1[i]<=t[i]){
							ans=min(ans, f[i-1][j][1][sum-1]+ps2[j]+ps1[i]);	
						}
						ans=min(ans, f[i-1][j][1][sum]+ps2[j]+ps1[i]);					
    				}
    				else if(ty==1 && j+1<=n+1){
    					if(sum!=0 && f[i][j+1][1][sum-1]+x[j+1]-x[j]<=t[j]){
    						ans=min(ans, f[i][j+1][1][sum-1]+x[j+1]-x[j]);	
    					}
    					ans=min(ans, f[i][j+1][1][sum]+x[j+1]-x[j]);
    					
    					if(sum!=0 && f[i][j+1][0][sum-1]+ps2[j]+ps1[i]<=t[j]){
    						ans=min(ans, f[i][j+1][0][sum-1]+ps2[j]+ps1[i]);	
    					}
						ans=min(ans, f[i][j+1][0][sum]+ps2[j]+ps1[i]);
    				}
    				if(ans<oo){
    					res=max(res, sum);
    				}
    				f[i][j][ty][sum]=ans;
    			}
    		}
    	}
    }
    
    // cout << ps2[5]+ps1[1] << ' ';
    // cout << f[0][5][0][3] << ' ';
    
    cout << res;
    
    return 0;
}

Compilation message (stderr)

ho_t3.cpp: In function 'int main()':
ho_t3.cpp:38:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   38 |         freopen(".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~
ho_t3.cpp:39:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |         freopen(".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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