Submission #825789

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;
#define gc getchar_unlocked
#define fo(i,n) for(i=0;i<n;i++)
#define Fo(i,k,n) for(i=k;i<n;i++)
#define ll long long
#define si(x)	scanf("%d",&x)
#define sl(x)	scanf("%I64d",&x)
#define ss(s)	scanf("%s",s)
#define pb push_back
#define mp make_pair
#define F first
#define S second
#define clr(x) memset(x, 0, sizeof(x))
#define tr(it, a) for(auto it = a.begin(); it != a.end(); it++)
#define PI 3.1415926535897932384626
typedef pair<int, int>	pii;
typedef pair<ll, ll>	pll;
typedef vector<int>		vi;
typedef vector<ll>		vl;
typedef vector<pii>		vpii;
typedef vector<pll>		vpll;
typedef vector<vi>		vvi;
typedef vector<vl>		vvl;
const int mod = 1000000007;
const int N = 2e5;
vi g[N];
ll a[N] ,cnt[N];

int mpow(int base, int exp); 
void ipgraph(int n, int m);
void dfs(int u, int par);
ll n, L;
vector<ll> ans;

bool go(int lo, int hi, ll sum){
	if (sum<L)return false;
	if (lo+1 == hi){
		ans.pb(lo+1);
		return true;
	}
	ll x = a[lo];
	ll y = a[hi];
	
	if (x<=y and go(lo+1, hi, sum-x)){
		ans.pb(lo+1);
		return true;
	} 
	if (x>y and go(lo, hi-1, sum-y)){
		ans.pb(hi);
		return true;
	} 
	return false;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	string no = "Impossible\n";
	string yes = "Possible\n";
	cin>>n>>L;
	int i;
	ll sum = 0;
	int lo = 0, hi = n-1;
	fo(i, n) cin>>a[i], sum += a[i];
	if (sum < L){
		cout<<no;
		return 0;
	}
	if (go(0, n-1, sum)){
		cout<<yes;
		// cout<<ans.size()<<endl;
		fo(i, ans.size()){
			cout<<ans[ans.size()-1-i]<<endl;
		}
	}
	else{
		cout<<no;
	}
	// while(lo+1<=hi){
	// 	ll x, y;
	// 	x = a[lo];
	// 	y = a[hi];
		
	// }
	
	return 0;
} 

int mpow(int base, int exp) {
  base %= mod;
  int result = 1;
  while (exp > 0) {
    if (exp & 1) result = ((ll)result * base) % mod;
    base = ((ll)base * base) % mod;
    exp >>= 1;
  }
  return result;
}

void ipgraph(int n, int m){
	int i, u, v;
	while(m--){
		cin>>u>>v;
		g[u-1].pb(v-1);
		g[v-1].pb(u-1);
	}
}

void dfs(int u, int par){
	for(int v:g[u]){
		if (v == par) continue;
		dfs(v, u);
	}
}

Submission Info

Judge Result