1117. Eddington Number(25)

British astronomer Eddington liked to ride a bike. It is said that in order to show off his skill, he has even defined an "Eddington number", E -- that is, the maximum integer E such that it is for E days that one rides more than E miles. Eddington's own E was 87.

Now given everyday's distances that one rides for N days, you are supposed to find the corresponding E (<=N).

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N(<=10⁵), the days of continuous riding. Then N non-negative integers are given in the next line, being the riding distances of everyday.

Output Specification:

For each case, PRint in a line the Eddington number for these N days.

106 7 6 9 3 10 8 2 7 8Sample Output:
6
#include <cstdio>#include <algorithm>using namespace std;int a[1000000];bool cmp1(int a, int b) {	return a > b;}int main() {	int n;	scanf("%d", &n);	for (int i = 1; i <= n; i++) {		scanf("%d", &a[i]);	}	sort(a + 1, a + n + 1, cmp1);//從大到小排序	int ans = 0;	int p = 1;	while (ans <= n && a[p] > p) {//若滿足，那么1~p-1對應的數肯定是大于p的，然后如果a[p]>p那么剛好就滿足那個愛丁頓數		ans++;		p++;	}	printf("%d", ans);	return 0;}