https://codeforces.me/contest/1418/submission/92798564
#include <algorithm>
#include <array>
#include <cassert>
#include <iostream>
#include <vector>
using namespace std;
template<typename T> ostream& operator<<(ostream &os, const vector<T> &v) { os << '{'; string sep; for (const auto &x : v) os << sep << x, sep = ", "; return os << '}'; }
template<typename T, size_t size> ostream& operator<<(ostream &os, const array<T, size> &arr) { os << '{'; string sep; for (const auto &x : arr) os << sep << x, sep = ", "; return os << '}'; }
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
void dbg_out() { cerr << endl; }
template<typename Head, typename... Tail> void dbg_out(Head H, Tail... T) { cerr << ' ' << H; dbg_out(T...); }
#ifdef NEAL_DEBUG
#define dbg(...) cerr << "(" << #__VA_ARGS__ << "):", dbg_out(__VA_ARGS__)
#else
#define dbg(...)
#endif
const int INF = 1e9 + 5;
void run_case() {
int N;
cin >> N;
vector<int> A(N);
for (auto &a : A)
cin >> a;
vector<array<int, 2>> dp(N + 1, {INF, INF});
dp[0][1] = 0;
for (int i = 0; i < N; i++)
for (int who = 0; who < 2; who++)
for (int fight = 1; fight <= min(N - i, 2); fight++) {
int hard = A[i] + (fight > 1 ? A[i + 1] : 0);
dp[i + fight][!who] = min(dp[i + fight][!who], dp[i][who] + who * hard);
}
cout << min(dp[N][0], dp[N][1]) << '\n';
}
int main() {
ios::sync_with_stdio(false);
#ifndef NEAL_DEBUG
cin.tie(nullptr);
#endif
int tests;
cin >> tests;
while (tests-- > 0)
run_case();
}
can you help me explain these code?