Submission #233856

#	Time	Username	Problem	Language	Result	Execution time	Memory
233856		LittleFlowers__	Divide and conquer (IZhO14_divide)	C++17	100 / 100	61 ms	7276 KiB

divide

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define in ({int x=0;int c=getchar(),n=0;for(;!isdigit(c);c=getchar()) n=(c=='-');for(;isdigit(c);c=getchar()) x=x*10+c-'0';n?-x:x;})
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r){return l+rng()%(r-l+1);}
#define fasty ios_base::sync_with_stdio(0),cin.tie(0);
#define forinc(a,b,c) for(int a=b,_c=c;a<=_c;++a)
#define fordec(a,b,c) for(int a=b,_c=c;a>=_c;--a)
#define forv(a,b) for(auto&a:b)
#define fi first
#define se second
#define pb push_back
#define ii pair<int,int>
#define mt make_tuple
#define all(a) a.begin(),a.end()
#define reset(f, x) memset(f, x, sizeof(f))
#define bit(x,i) ((x>>(i-1))&1)
#define on(x,i) (x|(1ll<<(i-1)))
#define off(x,i) (x&~(1<<(i-1)))
#define gg exit(0);

const int N=100010;

int n;
int x[N],g[N],s[N],bit[N];
vector<int> val;

void upd(int i,int x){
    i=lower_bound(all(val),i)-val.begin()+1;
    for(;i;i-=i&-i) bit[i]=min(bit[i],x);
}
int que(int i){
    i=lower_bound(all(val),i)-val.begin()+1;
    int ret=bit[0];
    for(;i<=n;i+=i&-i) ret=min(ret,bit[i]);
    return ret;
}

main(){
    #define task "dnc"
    //freopen(task".inp","r",stdin);
    //freopen(task".out","w",stdout);

    n=in;
    forinc(i,1,n){
        x[i]=in;
        g[i]=g[i-1]+in;
        s[i]=s[i-1]+in;
        val.push_back(x[i]-s[i-1]);
    }
    /**
    x[i] - x[j] <= s[i] - s[j-1]
    x[i]-s[i] <= x[j]-s[j-1]
	g[i]-g[j-1] = max
    */
    reset(bit,127);
    int ret=0;
    sort(all(val));
    forinc(i,1,n){
        upd(x[i]-s[i-1],g[i-1]);
        ret=max(ret,g[i]-que(x[i]-s[i]));
    }
    cout<<ret;
}

Compilation message (stderr)

divide.cpp:40:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^

• Subtask 1: 17 / 17
• Subtask 2: 31 / 31
• Subtask 3: 52 / 52