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Submission #968066

# Submission time Handle Problem Language Result Execution time Memory
968066 2024-04-23T07:30:58 Z weakweakweak Line Town (CCO23_day1problem3) C++17
0 / 25
 1 ms 4444 KB 
#include <bits/stdc++.h>
using namespace std;

int n, a[500010], pre[500100], suf[500100];

int main () {
    ios_base::sync_with_stdio(false); cin.tie(0);
    cin >> n;
    for (int i = 1; i <= n; i++) cin >> a[i];
    for (int i = 0; i <= n; i++) pre[i] = suf[i] = INT_MAX / 3;
    pre[0] = 0;
    for (int i = 1; i <= n; i++) {
        if (a[i] == -1) pre[i] = pre[i - 1];
        if (i > 1 and a[i] == 1 and a[i - 1] == 1) pre[i] = min(pre[i], pre[i - 2] + 1);
    }
    suf[0] = 0;
    for (int i = 1; i <= n; i++) {
        int j = n + 1 - i;
        if (a[j] == 1) suf[i] = suf[i - 1];
        if (i > 1 and a[j] == -1 and a[j + 1] == -1) suf[i] = min(suf[i], suf[i - 2] + 1); 
    }

    int ans = suf[0] + pre[n];
    for (int i = 1; i <= n; i++) ans = min(ans, suf[i - 1] + pre[n - i]);

    if (ans > n / 2) ans = -1;
    cout << ans << '\n';
return 0;}

Subtask #1
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4444 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4444 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #3
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4444 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4444 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #5
0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4440 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #6
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4440 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0 / 2.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4444 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #8
0 / 3.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4444 KB Output is correct
2 Incorrect 1 ms 4444 KB Output isn't correct
3 Halted 0 ms 0 KB -