static void Method(string[] args)
{
int n = ReadInt();
int[] array = ReadInts();
for (int i = 0; i < n; i++)
{
array[i] = Min(array[i], i + 1);
}
int res = 0;
int tmpNow = 0;
GeneralPriorityQueue <int> queue = new GeneralPriorityQueue <int>();
for (int i = n - 1; i >= 0; i--)
{
queue.Enqueue(-array[i]);
if (tmpNow < n - i)
{
res++;
tmpNow += -queue.Dequeue();
}
}
WriteLine(res);
}
static List <int[]> AstarSearch(bool[,] grid, int sX, int sY, int gX, int gY)
{
var opens = new GeneralPriorityQueue <NodeInfo>();
opens.Enqueue(new NodeInfo(sX, sY, null, 0, Abs(gX - sX) + Abs(gY - sY)));
var closed = new List <NodeInfo>();
int[] dx = new int[4] {
1, 0, -1, 0
};
int[] dy = new int[4] {
0, 1, 0, -1
};
int h = grid.GetLength(0);
int w = grid.GetLength(1);
bool[,] visited = new bool[h, w];
while (opens.Count > 0)
{
NodeInfo now = opens.Dequeue();
if (visited[now.y, now.x])
{
continue;
}
visited[now.y, now.x] = true;
closed.Add(now);
if (now.x == gX && now.y == gY)
{
break;
}
for (int i = 0; i < 4; i++)
{
int toX = now.x + dx[i];
int toY = now.y + dy[i];
if (toX < 0 || toX >= w || toY < 0 || toY >= h)
{
continue;
}
if (visited[toY, toX])
{
continue;
}
if (!grid[toY, toX])
{
continue;
}
int nextH = Abs(toX - gX) + Abs(toY - gY);
opens.Enqueue(new NodeInfo(toX, toY, now, now.c + 1, nextH));
}
}
List <int[]> path = new List <int[]>();
NodeInfo current = closed[closed.Count - 1];
if (!(current.x == gX && current.y == gY))
{
return(path);
}
path.Add(new int[2] {
current.x, current.y
});
while (current.parent != null)
{
current = current.parent;
path.Add(new int[2] {
current.x, current.y
});
}
path.Reverse();
return(path);
}
static void Method(string[] args)
{
int[] nm = ReadInts();
int n = nm[0];
int m = nm[1];
int[][] abs = new int[m][];
for (int i = 0; i < m; i++)
{
abs[i] = ReadInts();
}
List <int>[] forwardGraph = new List <int> [n];
for (int i = 0; i < n; i++)
{
forwardGraph[i] = new List <int>();
}
int[] remainParents = new int[n];
for (int i = 0; i < m; i++)
{
forwardGraph[abs[i][0] - 1].Add(abs[i][1] - 1);
remainParents[abs[i][1] - 1]++;
}
GeneralPriorityQueue <int> que = new GeneralPriorityQueue <int>();
for (int i = 0; i < n; i++)
{
if (remainParents[i] == 0)
{
que.Enqueue(i);
}
}
List <int> resList = new List <int>();
while (que.Count > 0)
{
int now = que.Dequeue();
resList.Add(now + 1);
foreach (int child in forwardGraph[now])
{
remainParents[child]--;
if (remainParents[child] == 0)
{
que.Enqueue(child);
}
}
}
if (resList.Count == n)
{
WriteLine(string.Join(" ", resList));
}
else
{
WriteLine("-1");
}
}
