Submission #95437

#	Time	Username	Problem	Language	Result	Execution time	Memory
95437		choikiwon	K blocks (IZhO14_blocks)	C++17	100 / 100	183 ms	2300 KiB

blocks

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

typedef long long ll;
typedef pair<int, int> pii;

const int MN = 100010;

int N, K;
int A[MN], dp[2][MN];

struct Info {
    int h, mn, id;
};

int main() {
    scanf("%d %d", &N, &K);

    for(int i = 0; i < N; i++) {
        scanf("%d", &A[i]);
    }

    for(int i = N - 1; i >= 0; i--) {
        dp[1][i] = A[i];
        dp[1][i] = max(dp[1][i], dp[1][i + 1]);
    }
    for(int i = 2; i <= K; i++) {
        int p = (i & 1) ^ 1;
        int c = (i & 1);

        stack<Info> stk1;
        stack<pii> stk2;
        for(int j = N - i; j >= 0; j--) {
            int mn = dp[p][j + 1];
            while(!stk1.empty() && stk1.top().h <= A[j]) {
                mn = min(mn, stk1.top().mn);
                stk1.pop();
            }
            int t = stk1.empty()? N - i + 1 : stk1.top().id;
            while(!stk2.empty() && stk2.top().second < t) {
                stk2.pop();
            }
            stk1.push({A[j], mn, j});
            if(stk2.empty() || stk2.top().first > mn + A[j]) {
                stk2.push({mn + A[j], j});
            }
            dp[c][j] = stk2.top().first;

            //cout << i << ' ' << j << ' ' << dp[c][j] << endl;
        }
    }
    printf("%d", dp[K & 1][0]);
}

Compilation message (stderr)

blocks.cpp: In function 'int main()':
blocks.cpp:17:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &N, &K);
     ~~~~~^~~~~~~~~~~~~~~~~
blocks.cpp:20:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &A[i]);
         ~~~~~^~~~~~~~~~~~~

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