Submission #287894

#	Time	Username	Problem	Language	Result	Execution time	Memory
287894		tqbfjotld	Bigger segments (IZhO19_segments)	C++14	100 / 100	399 ms	48388 KiB

segments

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

set<pair<pair<int,int>,int> >s;
int arr[500005];
int suf[500005];
int ans[500005];

void add(pair<pair<int,int>,int> a){
    //printf("inserting %d %d %d\n",a);
    auto it = s.lower_bound(a);
    while (it!=s.end() && (*it).second<=a.second){
        it = s.erase(it);
    }
    if (it!=s.begin()){
        it--;
        if ((*it).second>a.second){
            return;
        }
    }
    s.insert(a);
}


 main(){
    int n;
    scanf("%lld",&n);
    for (int x = 0; x<n; x++){
        scanf("%lld",&arr[x]);
    }
    for (int x = n-1; x>=0; x--){
        suf[x] = suf[x+1]+arr[x];
    }
    s.insert({{-suf[0],0},0});
    for (int x = 0; x<n; x++){
        //printf("searching %d\n",-suf[x+1]);
        auto it = s.lower_bound({{-suf[x+1]+1,-1},-1});
        assert(it!=s.begin());
        it--;
        ans[x] = (*it).second+1;
        //printf("ans %d = %d\n",x,ans[x]);
        add({{suf[(*it).first.second]-2*suf[x+1],x+1},ans[x]});
    }
    printf("%lld",ans[n-1]);
}

Compilation message (stderr)

segments.cpp:26:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   26 |  main(){
      |       ^
segments.cpp: In function 'int main()':
segments.cpp:28:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   28 |     scanf("%lld",&n);
      |     ~~~~~^~~~~~~~~~~
segments.cpp:30:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   30 |         scanf("%lld",&arr[x]);
      |         ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 13 / 13
• Subtask 2: 14 / 14
• Subtask 3: 10 / 10
• Subtask 4: 36 / 36
• Subtask 5: 27 / 27