How Many Answers Are Wrong 并查集

题意为前两个数之间的和为第三个数，这个题我们可以这么考虑，比如a 到 b之间和为 s，那么 s = （开始到b之间的和） - （开始到a-1之间的和），ab的根相等 那么它们在一个集合里 那么s即为它们之间和 如果ab的根不相等，那么把b链接到a的根上  那么 更新 b的权值 它到a根的就为 （a到b的距离） + （ a到根的距离） - （b到原来的根）。可以自己画图分析一下

TT and FF are ... friends. Uh... very very good friends -________-b

FF is a bad boy, he is always wooing TT to play the following game with him. This is a very humdrum game. To begin with, TT should write down a sequence of integers-_-!!(bored).

Then, FF can choose a continuous subsequence from it(for example the subsequence from the third to the fifth integer inclusively). After that, FF will ask TT what the sum of the subsequence he chose is. The next, TT will answer FF's question. Then, FF can redo this process. In the end, FF must work out the entire sequence of integers.

Boring~~Boring~~a very very boring game!!! TT doesn't want to play with FF at all. To punish FF, she often tells FF the wrong answers on purpose.

The bad boy is not a fool man. FF detects some answers are incompatible. Of course, these contradictions make it difficult to calculate the sequence.

However, TT is a nice and lovely girl. She doesn't have the heart to be hard on FF. To save time, she guarantees that the answers are all right if there is no logical mistakes indeed.

What's more, if FF finds an answer to be wrong, he will ignore it when judging next answers.

But there will be so many questions that poor FF can't make sure whether the current answer is right or wrong in a moment. So he decides to write a program to help him with this matter. The program will receive a series of questions from FF together with the answers FF has received from TT. The aim of this program is to find how many answers are wrong. Only by ignoring the wrong answers can FF work out the entire sequence of integers. Poor FF has no time to do this job. And now he is asking for your help~(Why asking trouble for himself~~Bad boy)

 

Input

Line 1: Two integers, N and M (1 <= N <= 200000, 1 <= M <= 40000). Means TT wrote N integers and FF asked her M questions.

Line 2..M+1: Line i+1 contains three integer: Ai, Bi and Si. Means TT answered FF that the sum from Ai to Bi is Si. It's guaranteed that 0 < Ai <= Bi <= N.

You can assume that any sum of subsequence is fit in 32-bit integer.

 

Output

A single line with a integer denotes how many answers are wrong.

 

Sample Input

10 51 10 1007 10 281 3 324 6 416 6 1

 

Sample Output

1



#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#define N 200200

using namespace std;

int par[N],number[N];
int n,m;
int a,b,s;
void init(int n)
{
    memset(number,0,sizeof(number));
    for(int i = 1; i <= n; i ++)
        par[i] = i;
}
int fond(int x)
{
    if(x == par[x])
        return x;
    else
    {
        int temp = par[x];
        par[x] = fond(par[x]);
        number[x]+=number[temp];
        return par[x];
    }
}
int unionn(int a, int b, int s)
{
    int ans=0;
    int x = fond(a);
    int y = fond(b);
    if(x == y)
    {
        if(number[b] - number[a] != s)
            ans++;
    }
    else
    {
        par[y] = x;
        number[y]=number[a] - number[b] + s;
    }
   return ans;
}
int main()
{

    while(~scanf("%d%d",&n,&m))
   {

    init(n);
     int cut=0;
    for(int i = 1; i <= m; i++)
    {
        scanf("%d%d%d",&a,&b,&s);
        a--;
        cut += unionn(a,b,s);
    }
    printf("%d\n",cut);
   }
    return 0;
}