[PAT解题报告] Sort with Swap

#include <cstdio>
#include <cstring>
#include <string>

using namespace std;

bool mark[100005];
int a[100005];

int give(int x) {
int r = 0;
bool have = false;
    for (;!mark[x];++r) {
        if (x == 0) {
            have = true;
        }
        mark[x] = true;
        x = a[x];
    }
    return have?(r - 1):((r <= 1)?0:(r + 1));
}

int main() {
int n;
    scanf("%d",&n);
    for (int i = 0; i < n; ++i) {
        scanf("%d",a + i);
    }
    int answer = 0;
    for (int i = 0; i < n; ++i) {
        answer += give(a[i]);
    }
    printf("%d\n",answer);
    return 0;
}