Submission #1217311

#	Time	Username	Problem	Language	Result	Execution time	Memory
1217311		lmaobruh	K blocks (IZhO14_blocks)	C++20	0 / 100	3 ms	6728 KiB

blocks

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
static const ll INF = (1LL<<60);
static const int MAXN = 100000;

// --- segment tree range-add + global-min ---
struct Seg {
    struct Node { ll mn, lz; } st[4*MAXN];
    // build không cần, vì ta khởi lại bằng memset
    inline void apply(int p, ll v) {
        st[p].mn += v;
        st[p].lz += v;
    }
    inline void push(int p) {
        if (st[p].lz) {
            apply(p<<1,   st[p].lz);
            apply(p<<1|1, st[p].lz);
            st[p].lz = 0;
        }
    }
    inline void pull(int p) {
        st[p].mn = min(st[p<<1].mn, st[p<<1|1].mn);
    }
    // update range [i..j] += v
    void updR(int p, int l, int r, int i, int j, ll v) {
        if (i>r || j<l) return;
        if (i<=l && r<=j) {
            apply(p, v);
            return;
        }
        push(p);
        int m = (l+r)>>1;
        if (i <= m) updR(p<<1,   l, m, i, j, v);
        if (j >  m) updR(p<<1|1, m+1, r, i, j, v);
        pull(p);
    }
    // point set pos=idx to value (overwrite)
    void updP(int p, int l, int r, int idx, ll val) {
        if (l==r) {
            st[p].mn = val;
            st[p].lz = 0;
            return;
        }
        push(p);
        int m = (l+r)>>1;
        if (idx <= m) updP(p<<1,   l, m, idx, val);
        else          updP(p<<1|1, m+1, r, idx, val);
        pull(p);
    }
    inline ll query() const { 
        return st[1].mn; 
    }
} seg;

// --- globals ---
int N, K;
int A[MAXN+1];
ll dp_prev[MAXN+1], dp_cur[MAXN+1];
// stack: values và left‑indices
int stk_val[MAXN+1], stk_lft[MAXN+1], stk_sz;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    cin >> N >> K;
    for(int i = 1; i <= N; ++i) 
        cin >> A[i];

    // init dp_prev
    for(int i = 0; i <= N; ++i) 
        dp_prev[i] = (i==0 ? 0 : INF);

    while(K--){
        // reset segtree nodes [1..4N]
        memset(seg.st, 0x7f, sizeof seg.st);
        // xây lại mn = INF, lz = 0
        for(int p = 1; p < 4*(N+1); ++p){
            seg.st[p].mn = INF;
            seg.st[p].lz = 0;
        }
        stk_sz = 0;

        // i = 1 khởi tạo
        seg.updP(1, 0, N-1, 0, dp_prev[0]);
        stk_val[0] = A[1];
        stk_lft[0] = 0;
        stk_sz = 1;
        seg.updR(1, 0, N-1, 0, 0, A[1]);

        for(int i = 1; i <= N; ++i){
            if (i > 1){
                // 1) set dp_prev[i-1]
                seg.updP(1, 0, N-1, i-1, dp_prev[i-1]);

                // 2) xử lý A[i] với monotonic stack
                int L = i - 1;
                while(stk_sz > 0 && stk_val[stk_sz-1] <= A[i]){
                    int v  = stk_val[stk_sz-1];
                    int lf = stk_lft[stk_sz-1];
                    --stk_sz;
                    seg.updR(1, 0, N-1, lf, L-1, -v);
                    L = lf;
                }
                // push segment mới
                stk_val[stk_sz] = A[i];
                stk_lft[stk_sz] = L;
                ++stk_sz;
                seg.updR(1, 0, N-1, L, i-1, A[i]);
            }
            dp_cur[i] = seg.query();
        }

        // swap dp_prev / dp_cur
        memcpy(dp_prev, dp_cur, (N+1)*sizeof(ll));
    }

    cout << dp_prev[N];
    return 0;
}

• Subtask 1: 0 / 14
• Subtask 2: 0 / 18
• Subtask 3: 0 / 21
• Subtask 4: 0 / 47