oj.uz

Submission #287942

# Submission time Handle Problem Language Result Execution time Memory
287942 2020-09-01T07:06:56 Z PeppaPig Discharging (NOI20_discharging) C++14
20 / 100
 195 ms 4344 KB 
#include <bits/stdc++.h>

#define long long long

using namespace std;

const int N = 1e6 + 5;

struct CHT {
    struct line {
        long m, c;
        line(long m, long c) : m(m), c(c) {}
        long f(long x) { return m * x + c; }
    };
    int ptr = 0;
    vector<line> vec;

    bool bad(line a, line b, line c) {
        return (c.c - a.c) * (a.m - b.m) <= (b.c - a.c) * (a.m - c.m);
    }

    void add(long m, long c) {
        line l(m, c);
        while(vec.size() > 1 && bad(vec[(int)vec.size() - 2], vec.back(), l))
            vec.pop_back();
        vec.emplace_back(l);
    }

    long get_ans(long x) {
        while(ptr + 1 < (int)vec.size() && vec[ptr + 1].f(x) < vec[ptr].f(x)) 
            ++ptr;
        return vec[ptr].f(x);
    }
} hull;

int n, A[N];
long dp[N];
vector<int> stk;

int main() {
    scanf("%d", &n);
    for(int i = n; i; i--) scanf("%d", A + i);

    for(int i = 1; i <= n; i++) {
        while(!stk.empty() && A[stk.back()] <= A[i])
            stk.pop_back();
        stk.emplace_back(i);
    }
    for(int i = 0; i < (int)stk.size(); i++) {
        hull.add(A[stk[i]], dp[i - 1]);
        dp[i] = hull.get_ans(stk[i]);
    }

    printf("%lld\n", dp[(int)stk.size() - 1]);

    return 0;
}

Compilation message

Discharging.cpp: In function 'int main()':
Discharging.cpp:41:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   41 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
Discharging.cpp:42:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   42 |     for(int i = n; i; i--) scanf("%d", A + i);
      |                            ~~~~~^~~~~~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 256 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 0 ms 256 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 0 ms 256 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 0 ms 256 KB Output is correct
14 Correct 1 ms 256 KB Output is correct

Subtask #2
0 / 13.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
0 / 25.0

# Verdict Execution time Memory Grader output
1 Incorrect 1 ms 384 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
11.0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 184 ms 4224 KB Output is correct
2 Correct 195 ms 4164 KB Output is correct
3 Correct 180 ms 4216 KB Output is correct
4 Correct 180 ms 4216 KB Output is correct
5 Correct 183 ms 4216 KB Output is correct
6 Correct 183 ms 4344 KB Output is correct
7 Correct 180 ms 4216 KB Output is correct
8 Correct 182 ms 4220 KB Output is correct
9 Correct 188 ms 4328 KB Output is correct
10 Correct 182 ms 4216 KB Output is correct

Subtask #5
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 256 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 0 ms 256 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 0 ms 256 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 0 ms 256 KB Output is correct
14 Correct 1 ms 256 KB Output is correct
15 Incorrect 1 ms 384 KB Output isn't correct
16 Halted 0 ms 0 KB -

Subtask #6
0 / 28.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 256 KB Output is correct
2 Correct 0 ms 384 KB Output is correct
3 Correct 1 ms 384 KB Output is correct
4 Correct 0 ms 384 KB Output is correct
5 Correct 0 ms 384 KB Output is correct
6 Correct 0 ms 384 KB Output is correct
7 Correct 0 ms 256 KB Output is correct
8 Correct 1 ms 384 KB Output is correct
9 Correct 0 ms 256 KB Output is correct
10 Correct 0 ms 384 KB Output is correct
11 Correct 0 ms 256 KB Output is correct
12 Correct 0 ms 384 KB Output is correct
13 Correct 0 ms 256 KB Output is correct
14 Correct 1 ms 256 KB Output is correct
15 Incorrect 1 ms 384 KB Output isn't correct
16 Halted 0 ms 0 KB -