AtCoder Beginner Contest 430

D - Neighbor Distance

set模拟

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define pii pair<int,int>
#define ll long long
#define pb push_back
#define ft first
#define se second
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
#define int long long

const int N = 500010;
int a[N];
void solve(){
int n; cin >> n;
int ans = 0;
set<pii> s; s.insert({0, 0}); s.insert({1e18, -1});

for(int i = 1; i <= n; i ++){
    int x; cin >> x;
    if(i == 1){a[0] = x; ans += x;}
    auto t1 = s.lower_bound({x, -1});auto t = t1; t --;

    int tf = (*t).ft;int t1f = (*t1).ft;
    int ts = (*t).se; int t1s = (*t1).se;

    if(ts != -1){
        if(a[ts] > x - tf){
            ans += x - tf - a[ts];
            a[ts] = x - tf;
        }
    }
    if(t1s != -1){
        if(a[t1s] > t1f - x){
            ans += t1f - x - a[t1s];
            a[t1s] = t1f -x;
        }
    }
    a[i] = min(x - tf, t1f - x);
    ans += a[i];
    s.insert({x,i});
    cout << ans << '\n';
}

}
signed main(){
    std::ios::sync_with_stdio(false);
    int T=1;//cin>>T;
    while(T--){
        solve();
    }
}

F - Back and Forth Filling

每个可能的位置是[ls+1, n-rs]

#include<bits/stdc++.h>
using namespace std;
#define endl '\n'
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define pii pair<int,int>
#define ll long long
#define pb push_back
#define ft first
#define se second
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
#define int long long

const int N = 500010;
int a[N];
void solve(){
int n; cin >> n;
int ans = 0;
set<pii> s; s.insert({0, 0}); s.insert({1e18, -1});

for(int i = 1; i <= n; i ++){
    int x; cin >> x;
    if(i == 1){a[0] = x; ans += x;}
    auto t1 = s.lower_bound({x, -1});auto t = t1; t --;

    int tf = (*t).ft;int t1f = (*t1).ft;
    int ts = (*t).se; int t1s = (*t1).se;

    if(ts != -1){
        if(a[ts] > x - tf){
            ans += x - tf - a[ts];
            a[ts] = x - tf;
        }
    }
    if(t1s != -1){
        if(a[t1s] > t1f - x){
            ans += t1f - x - a[t1s];
            a[t1s] = t1f -x;
        }
    }
    a[i] = min(x - tf, t1f - x);
    ans += a[i];
    s.insert({x,i});
    cout << ans << '\n';
}

}
signed main(){
    std::ios::sync_with_stdio(false);
    int T=1;//cin>>T;
    while(T--){
        solve();
    }
}