func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long LL_INF = (long long)2e18 + 5;   struct point {     long long x, y;     point() : x(0), y(0) {}     point(long long _x, long long _y) : x(_x), y(_y) {}   };   struct reverse_monotonic_dp_hull {     vector<point> points;     int size() const { return (int)points.size(); }     void clear() {       points.clear();       prev_x = LL_INF;     }     static long long floor_div(long long a, long long b) {       return a / b - ((a ^ b) < 0 && a % b != 0);     }     static bool bad_middle(const point &a, const point &b, const point &c) {       return floor_div(a.y - b.y, b.x - a.x) >= floor_div(b.y - c.y, c.x - b.x);     }     void insert(const point &p) {       assert(size() == 0 || p.x >= points.back().x);       if (size() > 0 && p.x == points.back().x) {         if (p.y <= points.back().y) return;         points.pop_back();       }       while (size() >= 2 &&              bad_middle(points[points.size() - 2], points.back(), p))         points.pop_back();       points.push_back(p);     }     void insert(long long a, long long b) { insert(point(a, b)); }     long long prev_x = LL_INF;     long long query(long long x) {       assert(x <= prev_x);       prev_x = x;       while (size() >= 2 && x * (points.back().x - points[size() - 2].x) <=                                 points[size() - 2].y - points.back().y)         points.pop_back();       return points.back().x * x + points.back().y;     }   };   int N, K;   vector<long long> A;   vector<long long> dp, next_dp;   vector<long long> left_max, right_max;   void update(int start, int end) {     if (start >= end) return;     if (end - start == 1) {       next_dp[end] = min(next_dp[end], dp[start] + A[start]);       return;     }     int mid = (start + end) / 2;     update(start, mid);     left_max[mid] = right_max[mid] = -LL_INF;     for (int i = mid - 1; i >= start; i--)       left_max[i] = max(left_max[i + 1], A[i]);     for (int i = mid; i < end; i++) right_max[i + 1] = max(right_max[i], A[i]);     reverse_monotonic_dp_hull hull;     for (int right = mid + 1, left = mid; right <= end; right++) {       while (left >= start && right_max[right] >= left_max[left]) {         hull.insert(-left, -dp[left]);         left--;       }       if (hull.size() > 0)         next_dp[right] = min(next_dp[right], -hull.query(-right_max[right]) +                                                  right * right_max[right]);     }     hull.clear();     for (int right = end, left = start; right > mid; right--) {       while (left <= mid && left_max[left] >= right_max[right]) {         hull.insert(-left_max[left], left * left_max[left] - dp[left]);         left++;       }       if (hull.size() > 0)         next_dp[right] = min(next_dp[right], -hull.query(right));     }     update(mid + 1, end);   }   void update_dp() {     left_max.assign(N + 1, -LL_INF);     right_max.assign(N + 1, -LL_INF);     next_dp.assign(N + 1, LL_INF);     update(0, N);     swap(dp, next_dp);   }   int main() {     ios::sync_with_stdio(false);     cin.tie(nullptr);     cin >> N >> K;     A.resize(N);     for (auto &a : A) cin >> a;     dp.assign(N + 1, LL_INF);     dp[0] = 0;     for (int k = 0; k < K; k++) update_dp();     cout << dp[N] <<   n ;   }   