#1WA

#17#18#19#20TLE

#include <bits/stdc++.h>
using namespace std;
const int inf = 0x7FFFFFFF;
int i, j, l, n, minn = inf, a[100001];
int main() {
	cin >> n;
	for (i = 1; i <= n; i++) cin >> a[i];
	for (i = 2; i <= n; i++) {
		for (j = 1; j < i; j++) {
			if (minn > abs(a[i] - a[j])) minn = abs(a[i] - a[j]), l = j;
		}
		cout << minn << ' ' << l << endl;
		minn = inf, l = 0;
	}
	return 0;
}

$O(n^2)$代码