1117. Eddington Number(25)-PAT甲级真题

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.

Sample Input:
10
6 7 6 9 3 10 8 2 7 8
Sample Output:
6

题目大意:英国天文学家爱丁顿很喜欢骑车。据说他为了炫耀自己的骑车功力,还定义了一个“爱丁顿数”E,即满足有E天骑车超过E英里的最大整数E。据说爱丁顿自己的E等于87。
分析:在数组a中存储n天的公里数,对n个数据从大到小排序,i表示了骑车的天数,那么满足a[i] > i+1的最大i+1即为所求