P6926 [ICPC 2016 WF] String Theory

Sol

注意到数据范围很小，所以考虑直接枚举答案，暴力 check 即可。

Code

#include <bits/stdc++.h>
#define x first
#define y second
#define pb push_back
#define eb emplace_back
#define pf push_front
#define desktop "C:\\Users\\incra\\Desktop\\"
#define IOS ios :: sync_with_stdio (false),cin.tie (0),cout.tie (0)
#define debug(x) cerr << #x << ' ' << x << endl
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
typedef pair <int,int> PII;
const int dx[] = {1,0,-1,0},dy[] = {0,-1,0,1};
template <typename T1,typename T2> bool tomax (T1 &x,T2 y) {
	if (y > x) return x = y,true;
	return false;
}
template <typename T1,typename T2> bool tomin (T1 &x,T2 y) {
	if (y < x) return x = y,true;
	return false;
}
LL power (LL a,LL b,LL p) {
	if (!a) return 0;
	LL ans = 1;
	while (b) {
		if (b & 1) ans = ans * a % p;
		a = a * a % p;
		b >>= 1;
	}
	return ans;
}
int fastio = (IOS,0);
#define endl '\n'
#define puts(s) cout << (s) << endl
const int N = 110;
int n;
int a[N],b[N];
bool check (int x) {
	for (int i = 1;i <= n;i++) b[i] = a[i];
	int l = 1,r = n;
	int i;
	for (i = x;i > 1 && l <= r;i--) {
		if (b[l] < i) break;
		b[l] -= i;
		if (!b[l]) l++;
		if (b[r] < i) break;
		b[r] -= i;
		if (!b[r]) r--;
	}
	return l <= r && i == 1;
}
void mian () {
	cin >> n;
	int sum = 0;
	for (int i = 1;i <= n;i++) cin >> a[i],sum += a[i];
	if (sum & 1) {
		puts ("no quotation");
		return ;
	}
	for (int i = min (a[1],a[n]);i >= 2;i--) {
		if (check (i)) {
			cout << i << endl;
			return ;
		}
	}
	if (sum == 2) puts ("1");
	else puts ("no quotation");
}
int main () {
	int T = 1;
	// cin >> T;
	while (T--) mian ();
	return 0;
}