uoj206 [APIO2016]最大差分

ref

#include "gap.h"
#include <iostream>
#include <cstdio>
using namespace std;
typedef long long ll;
ll a[100005];
ll findGap(int T, int n){
	if(T==1){
		ll l=0, r=1000000000000000000ll, mn, mx;
		int lcnt=1, rcnt=n;
		while(lcnt<=rcnt && l<=r){
			MinMax(l, r, &mn, &mx);
			if(mn!=-1)	a[lcnt++] = mn;
			if(mx!=-1)	a[rcnt--] = mx;
			l = mn + 1;
			r = mx - 1;
		}
		ll re=0;
		for(int i=2; i<=n; i++)
			re = max(re, a[i]-a[i-1]);
		return re;
	}
	else{
		ll mn, mx;
		MinMax(0, 1000000000000000000ll, &mn, &mx);
		if(n<=2)	return mx-mn;
		ll lst=mn, len=(mx-mn-1)/(n-2)+1, s=mn+1, t, ans=0, lim=mx;
		for(int i=1; i<=n-2; i++){
			t = s + len - 1;
			if(t>=lim)	t = lim - 1;
			if(s>t)	break;
			MinMax(s, t, &mn, &mx);
			if(mx!=-1){
				ans = max(mn - lst, ans);
				lst = mx;
			}
			s = t + 1;
		}
		ans = max(ans, lim-lst);
		return ans;
	}
}