Submission #406080

#	Time	Username	Problem	Language	Result	Execution time	Memory
406080		zaneyu	The short shank; Redemption (BOI21_prison)	C++14	35 / 100	2089 ms	199268 KiB

prison

/*input
5 2 5
1 9 4 6 7
*/


#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> indexed_set;
//#pragma GCC optimize("O2","unroll-loops","no-stack-protector")
//order_of_key #of elements less than x
// find_by_order kth element
using ll=long long;
using ld=long double;
using pii=pair<int,int>;
#define f first
#define s second
#define pb push_back
#define REP(i,n) for(int i=0;i<n;i++)
#define REP1(i,n) for(int i=1;i<=n;i++)
#define FILL(n,x) memset(n,x,sizeof(n))
#define ALL(_a) _a.begin(),_a.end()
#define sz(x)(int)x.size()
#define SORT_UNIQUE(c)(sort(c.begin(),c.end()),c.resize(distance(c.begin(),unique(c.begin(),c.end()))))
const ll INF64=4e18;
const int INF=0x3f3f3f3f;
const ll MOD=998244353;
const ld PI=acos(-1);
const ld eps=1e-9;
#define lowb(x) x&(-x)
#define MNTO(x,y) x=min(x,(__typeof__(x))y)
#define MXTO(x,y) x=max(x,(__typeof__(x))y)
inline ll mult(ll a,ll b){
    if(a<0) a+=MOD;
    if(b<0) b+=MOD;
    if(a>=MOD) a%=MOD;
    if(b>=MOD) b%=MOD;
    return(a*b)%MOD;
}
inline ll mypow(ll a,ll b){
    if(b<=0) return 1;
    ll res=1LL;
    while(b){
        if(b&1) res=mult(res,a);
        a=mult(a,a);
        b>>=1;
    }
    return res;
}
const int maxn=5e3+5;
int dp[maxn],pv[maxn];
int cst[maxn][maxn];
int arr[maxn],b[maxn];
void calc(int l,int r,int optl,int optr){
    if(l>r) return;
    int mid=(l+r)/2;
    int op;
    dp[mid]=INF;
    for(int i=optl;i<=min(mid,optr);i++){
        if(dp[mid]>pv[i]+cst[i+1][mid]){
            dp[mid]=pv[i]+cst[i+1][mid];
            op=i;
        }
    }
    calc(l,mid-1,optl,op);
    calc(mid+1,r,op,optr);
}
int main(){
    int n,d,t;
    cin>>n>>d>>t;
    REP(i,n){
        cin>>arr[i];
    }
    REP(i,n){
        int cnt=0;
        for(int j=i;j<n;j++){
            if(j!=i) b[j]=min(arr[j],b[j-1]+1);
            else b[j]=arr[j];
            if(b[j]<=t) cnt++;
            cst[i][j]=cnt;
        }
    }
    REP(i,n) pv[i]=cst[0][i];
    int ans=INF;
    REP1(j,d){
        calc(0,n-1,0,n-1);
        REP(i,n) pv[i]=dp[i];
        MNTO(ans,dp[n-1]);
    }
    cout<<ans;
}

Compilation message (stderr)

prison.cpp: In function 'void calc(int, int, int, int)':
prison.cpp:68:9: warning: 'op' may be used uninitialized in this function [-Wmaybe-uninitialized]
   68 |     calc(l,mid-1,optl,op);
      |     ~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 0 / 10
• Subtask 3: 20 / 20
• Subtask 4: 0 / 10
• Subtask 5: 0 / 25
• Subtask 6: 0 / 20