Submission #1558509

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Source Code Expand

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

const int DIM = 1e5 + 5;

int prm[DIM];

int main(void) {
    ios::sync_with_stdio(false);
    
    int n, ans = 0;
    cin >> n;
    
    for (int i = 1; i <= n; ++i)
        cin >> prm[i];
    
    for (int i = 1, j = 1; i <= n; i = ++j) {
        if (prm[i] != i)
            continue;
        
        while (j < n and prm[j + 1] == j + 1)
            ++j;
        
        ans = ans + (j - i + 2) / 2;
    }
    
    cout << ans;
    return 0;
}

Submission Info

Judge Result