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SSLOJSSLOJSSLOJ 264726472647

DescriptionDescriptionDescription

There is a line segment of length n in the plane (also called a line segment). The following two operations can be performed:
1 x y adds another line segment from X to y
2 x Query How many line segments are there from X to x+1

InputInputInput

First line input n, m
Line 2~m+1, 3 numbers per row

OutputOutputOutput

For each query operation, the number of output lines

SampleSampleSample InputInputInput

7 5
2 3 
1 2 5
2 4
1 4 5
2 4

SampleSampleSample OutputOutputOutput

1
2
3

In fact, this example is false. (There is no correct example yet)

HintHintHint

[Data Scale] 
100% satisfies 1 < n < 100000, 1 < x < y < n

TrainTrainTrain ofofof ThoughtThoughtThought

Just count how many line segments cover each interval.

CodeCodeCode

#include<iostream>
#include<cstdio>

using namespace std;

int ans, n, m;

struct Tree
{
	int l, r, num;
}tree[400005];

void Build(int x, int L, int R)
{
	tree[x].l = L, tree[x].r = R;
	if (L + 1 >= R) return;
	int mid = (L + R) >> 1;
	Build(x * 2, L, mid);
	Build(x * 2 + 1, mid, R);
}//Don't talk too much about building a tree.

void Ins(int x, int L, int R)
{
	if (tree[x].l == L && tree[x].r == R) {
		tree[x].num ++;
		return ;
	}//Record how many line segments exactly cover the current interval	
	int mid = (tree[x].l + tree[x].r) >> 1;
	if (R <= mid) Ins(x * 2, L, R);
	 else if (L >= mid) Ins(x * 2 + 1, L, R);
	  else {
	  	Ins(x * 2, L, mid);
	  	Ins(x * 2 + 1, mid, R);
	  } 
} 

int Print(int x)
{
	while (x > 0)
	{
		ans += tree[x].num;
		x >>= 1;
	}
	return ans;
}//Statistical answers

int Count(int x, int L, int R)
{
	int mid = (tree[x].l + tree[x].r) >> 1;
	if (tree[x].l == L && tree[x].r == R) return Print(x);//Find out the location of the interval. 
	if (R <= mid) Count(x * 2, L, R);
	 else if (L >= mid) Count(x * 2 + 1, L, R);
	  else {
	  	Count(x * 2, L, mid);
	  	Count(x * 2 + 1, mid, R);
	  } 
}

int main()
{
	int x, y;
	scanf("%d%d", &n, &m);
	Build(1, 1, n);
	for (int i = 1; i <= m; ++i)
	{
		scanf("%d%d", &x, &y);
		Ins(1, x, y);
	}
	scanf("%d%d", &x, &y);
	printf("%d", Count(1, x, y));
	return 0;

}