题目链接：

题解：

1 #include 
     
       2 using namespace std; 3 const int MAXN = 10000 + 5; 4  5 int main() { 6     int n; 7     cin >> n; 8     int *p = new int[n]; 9     for (int i = 0; i < n; i++) {10         cin >> p[i];11     }12     int ans[MAXN] = { 0 };13     for (int i = 0; i < n; i++) {14         int temp = p[i] - i - 1;15         if (temp < 0) temp = -temp;16         ans[temp]++;17     }18     for (int i = MAXN - 1; i >= 0; i--) //从大到小输出19         if (ans[i] > 1) cout << i << " " << ans[i] << endl;20     return 0;21 }