Submission #970432

#	Time	Username	Problem	Language	Result	Execution time	Memory
970432		yeediot	Watching (JOI13_watching)	C++17	100 / 100	232 ms	31932 KiB

watching

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define F first
#define S second
#define all(x) x.begin(),x.end()
#define pii pair<int,int>
#define pb push_back
#define sz(x) (int)(x.size())
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
#define vi vector<int>
#define vp vector<pii>
#define vvi vector<vi>
#define ykh mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count())
#define __lg(x) 63-__builtin_clzll(x)
#define pow2(x) (1LL<<x)
void __print(int x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef local
void setio(){freopen("/Users/iantsai/Library/Mobile Documents/com~apple~CloudDocs/cpp/Empty.md","r",stdin);}
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
void setio(){}
#define debug(x...)
#endif
void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
struct line{
    int a,b;
    int operator()(const int x)const{
        return a*x+b;
    }
};
bool check(line l1,line l2,line l3){
    return (l3.b-l2.b)*(l1.a-l2.a)<=(l2.b-l1.b)*(l2.a-l3.a);
}
signed main(){
    setio();
    ios::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    int n,p,q;
    cin>>n>>p>>q;
    vector<int>pos(n+1);
    for(int i=1;i<=n;i++){
        cin>>pos[i];
    }
    sort(all(pos));
    p=min(p,n);
    q=min(q,n);
    int l=1,r=1e9;
    while(l<r){
        int mm=l+r>>1;
        int dp[n+1][q+1];
        int from[2][n+1];
        int R=0;
        for(int j=0;j<2;j++){
            R=0;
            for(int i=1;i<=n;i++){
                while(R+1<=n and pos[R+1]<pos[i]-(j+1)*mm+1)
                    R++;
                from[j][i]=R;
            }
        }
        memset(dp,0x3f3f3f3f,sizeof(dp));
        for(int i=0;i<=q;i++){
            dp[0][i]=0;
        }
        for(int i=1;i<=n;i++){
            for(int j=0;j<=q;j++){
                dp[i][j]=min(dp[from[0][i]][j]+1,(j?dp[from[1][i]][j-1]:(int)1e18));
                //debug(i,j,dp[i][j],from[0][i],from[1][i]);
            }
        }
        if(dp[n][q]<=p){
            r=mm;
        }
        else{
            l=mm+1;
        }
        //debug(r,dp[n][q]);
    }
    cout<<l<<'\n';
}
 /*
 input:
 
 */















 

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:69:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   69 |         int mm=l+r>>1;
      |                ~^~
watching.cpp: In function 'void setIO(std::string)':
watching.cpp:42:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
watching.cpp:43:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   43 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50