代码

int binary_search(const unsigned *a, int n, unsigned x)
{
int L = 0, R = 100000000 - 1;
	for(; L < R; ) {
int md = (long long) (R * a[L] + L * a[R]) / (a[L] + a[R]);
if(a[md] == x) return md; else if(a[md] < x) L = md + 1; else R = md - 1;
}
	return 233;
}

评测结果